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Scientific American Supplement, No. 286 June 25, 1881

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Title: Scientific American Supplement, No. 286

June 25, 1881

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SCIENTIFIC AMERICAN SUPPLEMENT NO. 286

NEW YORK, JUNE 25, 1881

Scientific American Supplement. Vol. XI, No. 286.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

* * * * *

TABLE OF CONTENTS.

I. ENGINEERING AND MECHANICS.--One Thousand Horse Power Corliss Engine.

5 figures, to scale, illustrating the construction of the new one

thousand horse power Corliss engine, by Hitch, Hargreaves & Co.

Opening of the New Workshop of the Stevens Institute of Technology.

Speech of Prof. R.W. Raymond, speech of Mr. Horatio Allen.

Light Steam Engine for Aeronautical Purposes. Constructed for Capt.

Mojoisky, of the Russian Navy.

Complete Prevention of Incrustation in Boilers. Arrangement for

purifying boiler water with lime and carbonate of soda.--The

purification of the water.--Examination of the purified

water.--Results of water purification.

Eddystone Lighthouse. Progress of the work.

Rolling Mill for Making Corrugated Iron. 1 figure. The new mill of

Schultz, Knaudt & Co., of Essen, Germany.

Railway Turntable in the Time of Louis XIV. 1 figure. Pleasure car.

Railway and turntable at Mary-le-Roy Chateau, France, in 1714.

New Signal Wire Compensator. Communication from A. Lyle, describing

compensators in use on the Nizam State Railway, East India.

Tangye's Hydraulic Hoist. 2 figures.

Power Loom for Delicate Fabrics. 1 figure.

How Veneering is Made.

II. TECHNOLOGY AND CHEMISTRY.--The Constituent Parts of Leather. The

ads:

composition of different leathers exhibited at the Paris

Exhibition.--Amount of leather produced by different tonnages of 100

pounds of hides.--Percentage of tannin absorbed under different

methods of tanning.--Amounts of gelatine and tannin in leather of

different tonnages, etc.

Progress in American Pottery.

Photographic Notes.--Mr. Waruerke's New Discovery.--Method of

converting negatives directly into positives.--Experiments of Capt.

Bing on the sensitiveness of coal oil--Bitumen plates.--Method of

topographic engraving. By Commandant DE LA NOE.--Succinate of Iron

Developer.--Method of making friable hydro-cellulose.

Photo-Tracings in Black and Color.

Dyeing Reds with Artificial Alizarin. By M. MAURICE PRUD'HOMME.

III. ELECTRICITY, PHYSICAL SCIENCE, ETC.--On Faure's Secondary Battery.

Physical Science in Our Common Schools.--An exceptionally strong

argument for the teaching of physical science by the experimental

method in elementary schools, with an outline of the method and the

results of such teaching.

On the Law of Avogadro and Ampere. By E. VOGEL.

IV. GEOGRAPHY, GEOLOGY, ETC.--Petroleum and Coal in Venezuela.

Geographical Society of the Pacific.

The Behring's Straits Currents.--Proofs of their existence.

Experimental Geology.--Artificial production of calcareous pisolites

and oolites.--On crystals of anhydrous lime.--4 figures.

V. NATURAL HISTORY, ETC.--Coccidae. By Dr. H. BEHR.--An important paper

read before the California Academy of Sciences.--The marvelous

fecundity of scale bugs.--Their uses.--Their ravages.--Methods of

destroying them.

Agricultural Items.

Timber Trees.

Blood Rains.

VI. MEDICINE AND HYGIENE.--Medical Uses of Figs.

Topical Medication in Phthisis.

VII. ARCHITECTURE, ETC.--Suggestions in Architecture.--Large

illustration.--The New High School for Girls, Oxford, England.

* * * * *

PETROLEUM AND COAL IN VENEZUELA.

MR. E. H. PLUMACHER, U. S. Consul at Maracaibo, sends to the State

Department the following information touching the wealth of coal and

petroleum probable in Venezuela:

The asphalt mines and petroleum fountains are most abundant in that part

of the country lying between the River Zulia and the River Catatumbo,

and the Cordilleras. The wonderful sand-bank is about seven kilometers

from the confluence of the Rivers Tara and Sardinarte. It is ten meters

high and thirty meters long. On its surface can be seen several round

holes, out of which rises the petroleum and water with a noise like that

made by steam vessels when blowing off steam, and above there ascends a

column of vapor. There is a dense forest around this sand-bank, and the

place has been called "El Inferno." Dr. Edward McGregor visited the

sand-bank, and reported to the Government that by experiment he had

ascertained that one of the fountains spurted petroleum and water at the

rate of 240 gallons per hour. Mr. Plumacher says that the petroleum is

of very good quality, its density being that which the British market

requires in petroleum imported from the United States. The river, up to

the junction of the Tara and Sardinarte, is navigable during the entire

year for flat-bottomed craft of forty or fifty tons.

Mr. Plumacher has been unable to discover that there are any deposits

of asphalt or petroleum in the upper part of the Department of Colon,

beyond the Zulia, but he has been told that the valleys of Cucuta and

the territories of the State of Tachira abound in coal mines. There are

coal mines near San Antonia, in a ravine called "La Carbonera," and

these supply coal for the smiths' forges in that place. Coal and asphalt

are also found in large quantities in the Department of Sucre. Mr.

Plumacher has seen, while residing in the State of Zulia, but one true

specimen of "lignite," which was given to him by a rich land-owner,

who is a Spanish subject. In the section where it was found there are

several fountains of a peculiar substance. It is a black liquid, of

little density, strongly impregnated with carbonic acid which it

transmits to the water which invariably accompanies it. Deposits of this

substance are found at the foot of the spurs of the Cordilleras, and are

believed to indicate the presence of great deposits of anthracite.

There are many petroleum wells of inferior quality between Escuque and

Bettijoque, in the town of Columbia. Laborers gather the petroleum in

handkerchiefs. After these become saturated, the oil is pressed out by

wringing. It is burned in the houses of the poor. The people thought, in

1824, that it was a substance unknown elsewhere, and they called it

the "oil of Columbia." At that time they hoped to establish a valuable

industry by working it, and they sent to England, France, and this

country samples which attracted much attention. But in those days no

method of refining the crude oil had been discovered, and therefore

these efforts to introduce petroleum to the world soon failed.

The plains of Ceniza abound in asphalt and petroleum. There is a large

lake of these substances about twelve kilometers east of St. Timoteo,

and from it some asphalt is taken to Maracaibo. Many deposits of asphalt

are found between these plains and the River Mene. The largest is that

of Cienega de Mene, which is shallow. At the bottom lies a compact

bed of asphalt, which is not used at present, except for painting

the bottoms of vessels to keep off the barnacles. There are wells of

petroleum in the State of Falcon.

Mr. Plumacher says that all the samples of coal submitted to him in

Venezuela for examination, with the exception of the "lignite" before

mentioned, were, in his opinion, asphalt in various degrees of

condensation. The sample which came from Tule he ranks with the coals

of the best quality. He believes that the innumerable fountains and

deposits of petroleum, bitumen, and asphalt that are apparent on the

surface of the region around Lake Maracaibo are proof of the existence

below of immense deposits of coal. These deposits have not been

uncovered because the territory remains for the most part as wild as it

was at the conquest.

* * * * *

ONE THOUSAND HORSE-POWER CORLISS ENGINE.

[Illustration: FIG. 1.

DIA. OF CYLINDER = 40''

STROKE = 10 ft.

REVS = 41

SCALE OF DIAGRAMS 40 LBS = 1 INCH

FIG. 2.]

We illustrate one of the largest Corliss engines ever constructed. It is

of the single cylinder, horizontal, condensing type, with one cylinder

40 inches diameter, and 10 feet stroke, and makes forty-five revolutions

per minute, corresponding to a piston speed of 900 feet per minute. At

mid stroke the velocity of the piston is 1,402 feet per minute nearly,

and its energy in foot pounds amounts to about 8.6 times its weight.

The cylinder is steam jacketed on the body and ends, and is fitted with

Corliss valves and Inglis & Spencer's automatic Corliss valve expansion

gear. Referring to the general drawing of the engine, it will be seen

that the cylinder is bolted directly to the end of the massive cast iron

frame, and the piston coupled direct to the crank by the steel piston

rod and crosshead and the connecting rod. The connecting rod is 28

feet long center to center, and 12 inches diameter at the middle. The

crankshaft is made of forged Bolton steel, and is 21 inches diameter at

the part where the fly-wheel is carried. The fly driving wheel is 35

feet in diameter, and grooved for twenty-seven ropes, which transmit the

power direct to the various line shafts in the mill. The rope grooves

are made on Hick, Hargreaves & Co.'s standard pattern of deep groove,

and the wheel, which is built up, is constructed on their improved plan

with separate arms and boss, and twelve segments in the rim with joints

planed to the true angle by a special machine designed and made by

themselves. The weight of the fly-wheel is about 60 tons. The condensing

apparatus is arranged below, so that there is complete drainage from the

cylinder to the condenser. The air pump, which is 36 inches diameter and

2 feet 6 inches stroke, is a vertical pump worked by wrought iron

plate levers and two side links, shown by dotted lines, from the main

crosshead. The engine is fenced off by neat railing, and a platform with

access from one side is fitted round the top of the cylinder for getting

conveniently to the valve spindles and lubricators. The above engraving,

which is a side elevation of the cylinder, shows the valve gear

complete. There are two central disk plates worked by separate

eccentrics, which give separate motion to the steam and exhaust valves.

The eccentrics are mounted on a small cross shaft, which is driven by a

line shaft and gear wheels. The piston rod passes out at the back end of

the cylinder and is carried by a shoe slide and guide bar, as shown more

fully in the detailed sectional elevation through the cylinder, showing

also the covers and jackets in section. The cylinder, made in four

pieces, is built up on Mr. W. Inglis's patent arrangement, with separate

liner and steam jacket casing and separate end valve chambers. This

arrangement simplifies the castings and secures good and sound ones. The

liner has face joints, which are carefully scraped up to bed truly to

the end valve chambers. The crosshead slides are each 3 feet 3 inches

long and I foot 3 inches wide. The engine was started last year, and

has worked beautifully from the first, without heating of bearings or

trouble of any kind, and it gives most uniform and steady turning. It is

worked now at forty-one revolutions per minute, or only 820 feet piston

speed, but will be worked regularly at the intended 900 feet piston

speed per minute when the spinning machinery is adapted for the increase

which the four extra revolutions per minute of the engine will give; the

load driven is over 1,000 horsepower, the steam pressure being 50 lb.

to 55 lb., which, however, will be increased when the existing boilers,

which are old, come to be replaced by new. Indicator diagrams from the

engines are given on page 309. The engine is very economical in steam

consumption, but no special trials or tests have been made with it. An

exactly similar engine, but of smaller size, with a cylinder 30 inches

diameter and 8 feet stroke, working at forty-five revolutions per

minute, made by Messrs. Hick, Hargreaves & Co. for Sir Titus Salt,

Sons & Co.'s mill at Saltaire, was tested about two years ago by Mr.

Fletcher, chief engineer of the Manchester Steam Users' Association, and

the results which are given below pretty fairly represent the results

obtained from this class of engine. Messrs. Hick, Hargreaves & Co. are

now constructing a single engine of the same type for 1,800 indicated

horse-power for a cotton mill at Bolton; and they have an order for a

pair of horizontal compound Corliss engines intended to indicate 3,000

horse-power. These engines will be the largest cotton mill engines in

the world.--_The Engineer_.

[Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK. HARGREAVES &

CO.]

_Result of Trials with Saltaire Horizontal Engine on February 14th and

15th, 1878. Trials made by Mr. L.E. Fletcher, Chief Engineer Steam

Users' Association, Manchester._

Engine single-cylinder, with Corliss valves. Inglis and Spencer's valve

gear. Diameter of cylinder. 30in.; stroke, 8ft.; 45 revolutions per

minute.

No. of trials

Total 1.H.P.

[MB] Mean boiler pressure.

[MP] Mean pressure on piston at beginning of stroke.

[ML] Mean loss between boiler pressure and cylinder.

[MA] Mean average pressure on piston.

[W] Water Per I.H.P. per hour.

[C] Coal per I.H.P. per hour.

No. of trials Total MB MP ML MA W C

I.H.P. lb lb lb lb lb lb

Trial No. 1. 301.89 46.6 44.11 2.53 21.23 18.373 2.699

Trial No. 2. 309.66 47.63 44.45 3.18 21.67 17.599 2.561

Means. 305.775 47.115 44.28 2.855 21.45 17.986 2.630

[Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK, HARGREAVES

& CO.] [Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK,

HARGREAVES & CO.]

* * * * *

OPENING OF THE NEW WORKSHOP OF THE STEVENS INSTITUTE OF TECHNOLOGY.

In our SUPPLEMENT No. 283 we gave reports of some of the addresses of

the distinguished speakers, and we now present the remarks of Prof.

Raymond and Horatio Allen, Esq.:

SPEECH OF PROF. R. W. RAYMOND.

A few years ago, at one of the meetings of our Society of Civil

Engineers we spent a day or so in discussing the proper mode of

educating young men so as to fit them for that profession. It is a

question that is reopened for us as soon as we arrive at the age when

we begin to consider what career to lay out for our sons. When we were

young, the only question with parents in the better walks of life was,

whether their sons should be lawyers, physicians, or ministers. Anything

less than a professional career was looked upon as a loss of caste, a

lowering in the social scale. These things have changed, now that we

engineers are beginning to hold up our heads, as we have every reason to

do; for the prosperity and well-being of the great nations of the world

are attributable, perhaps, more to our efforts than to those of any

other class. When, in the past, the man of letters, the poet, the

orator, succeeded, by some fit expression, by some winged word, to

engage the attention of the world concerning some subject he had at

heart, the highest praise his fellow man could bestow was to cry out

to him, "Well said, well said!" But now, when, by our achievements,

commerce and industry are increased to gigantic proportions, when the

remotest peoples are brought in ever closer communication with us, when

the progress of the human race has become a mighty torrent, rushing

onward with ever accelerating speed, we glory in the yet higher praise,

"Well done, well done!" Under these circumstances, the question how a

young man is best fitted for our profession has become one of increasing

importance, and three methods have been proposed for its solution.

Formerly the only point in debate was whether the candidate should go

first to the schools and then to the workshop, or first to the shop and

then to the schools. It was difficult to arrive at any decision; for of

the many who had risen to eminence as engineers, some had adopted

one order and some the other. There remained a third course, that of

combining the school and the shop and of pursuing simultaneously the

study of theory and the exercise of practical manipulation. Unforeseen

difficulties arose, however, in the attempt to carry out this, the most

promising method. The maintenance of the shop proved a heavy expense,

which it was found could not be lessened by the manufacture of salable

articles, because the work of students could not compete with that of

expert mechanics. It would require more time than could be allotted,

moreover, to convert students into skilled workmen. Various

modifications of this combination of theory and practice, including more

or less of the Russian system of instruction in shop-work, have been

tried in different schools of engineering, but never under so favorable

conditions as the present. With characteristic caution and good

judgment, President Morton has studied the operation of the scheme

of instruction adopted in the Stevens Institute, and, noting its

deficiencies, has now supplied them with munificent liberality, giving

to it a completeness that leaves seemingly nothing that could be

improved upon, even in a prayer or a dream. Still, no one will be more

ready to admit than he who has done all this, that it is not enough to

fit up a machine shop, be it never so complete, and light it with an

electric lamp. The decision as to its efficiency must come from the

students that are so fortunate as to be admitted to it. If such young

men, earnest, enthusiastic, with every incentive to exertion and every

advantage for improvement, here, where they can feel the throbbing of

the great heart of enterprise, within sight of bridges upon which their

services will be needed, within hearing of the whistles of a score of

railroads, and the bells of countless manufactories which will want

them; if such as these, trained under such instructors and amid such

surroundings, prove to be not fitted for the positions waiting for them

to fill, it will have been definitely demonstrated that the perfect

scheme is yet unknown.

SPEECH OF MR. HORATIO ALLEN.

Impressed with the very great step in advance which has been inaugurated

here this evening, I feel crowding upon me so many thoughts that I

cannot make sure that, in selecting from them, I may not leave unsaid

much that I should say, and say some things that I had better omit. Some

years ago, when asked by a wealthy gentleman to what machine-shop he had

best send his son, who was to become a mechanical engineer, I advised

him not to send him to any, but to fit up a shop for him where he could

go and work at what he pleased without the drudgery of apprenticeship,

to put him in the way of receiving such information as he needed, and

especially to let him go where he could see things break. Great, indeed,

are the advantages of those who have the opportunity of seeing things

break, of witnessing failures and profiting by them. When men have

enumerated the achievements of those most eminent in our profession the

thought has often struck me, "Ah! if we could only see that man's scrap

heap."

There are many who are able to construct a machine for a given purpose

so that it will work, but to do this so that it will not cost too much

is an entirely different problem. To know what to omit is a rare talent.

I once found a young man who could tell students what to store up in

their minds for immediate use, and what to skim over or omit; but I

could not keep him long, for more lucrative positions are always waiting

for such men.

The advice I gave my wealthy friend was given before the Stevens

Institute had developed in the direction it has now. The foundation of

this advice, namely, to combine a certain amount of judicious practice

with theory, is now in a fair way to be carried out, and although

things will probably not be permitted to break here, the students will

doubtless have opportunities for looking around them and supplementing

their systematic instruction here by observation abroad.

* * * * *

LIGHT STEAM ENGINE FOR BALLOONS.

We here illustrate one of a couple of compound engines designed and

constructed by Messrs. Ahrbecker, Son & Hamkens, of Stamford Street,

S.E., for Captain Mojaisky, of the Russian Imperial Navy, who intends

to use them for aeronautical purposes. The larger of these engines has

cylinders 33/4 in. and 71/2 in. in diameter and 5 in. stroke, and when

making 300 revolutions per minute it develops 20 actual horse

power, while its weight is but 105 lbs. The smaller engine--the one

illustrated--has cylinders 21/2 in. and 5 in. in diameter, and 31/2 in.

stroke, and weighs 63 lbs., while when making 450 revolutions it

develops 10 actual horse power.

The two engines are identical in design, and are constructed of forged

steel with the exception of the bearings, connecting-rods, crossheads,

slide valves and pumps, which are of phosphor-bronze. The cylinders,

with the steam passages, etc., are shaped out of the solid. The

standards, as will be seen, are of very light T steel, the crankshafts

and pins are hollow, as are also the crosshead bolts and piston rods.

The small engine drives a single-acting air pump of the ordinary type by

a crank, not shown in the drawing. The condenser is formed of a series

of hollow gratings.

[Illustration: LIGHT STEAM ENGINE FOR AERONAUTICAL PURPOSES]

Steam is supplied to the two engines by one boiler of the Herreshoff

steam generator type, with certain modifications, introduced by the

designers, to insure the utmost certainty in working. It is of steel,

the outside dimensions being 22 in. in diameter, 25 in. high, and weighs

142 lb. The fuel used is petroleum, and the working pressure 190 lb. per

square inch.

The constructors consider the power developed by these engines very

moderate, on account of the low piston speed specified in this

particular case. In some small and light engines by the same makers

the piston speed is as high as 1000 ft. per minute. The engines now

illustrated form an interesting example of special designing, and

Messrs. Ahrbecker, Son, and Hamkens deserve much credit for the manner

in which the work has been turned out, the construction of such light

engines involving many practical difficulties,--_Engineering._

* * * * *

Mount Baker, Washington Territory, has shown slight symptoms of volcanic

activity for several years. An unmistakable eruption is now in progress.

* * * * *

COMPLETE PREVENTION OF INCRUSTATION IN BOILERS.

The chemical factory, Eisenbuettel, near Braunschweig, distributes the

following circular: "The principal generators of incrustation in boilers

are gypsum and the so-called bicarbonates of calcium and magnesium. If

these can be taken put of the water, before it enters the boiler, the

formation of incrustation is made impossible; all disturbances and

troubles, derived from these incrustations, are done away with, and

besides this, a considerable saving of fuel is possible, as clear iron

will conduct heat quicker than that which is covered with incrustation."

J. Kolb, according to _Dingler's Polyt. Journal_, says: "A boiler with

clear sides yielded with 1 kil. coal 7.5 kil. steam, after two months

only 6.4 kil. steam, or a decrease of 17 per cent. At the same time the

boiler had suffered by continual working."

Suppose a boiler free from inside crust would yield a saving of only

5 per cent. in fuel (and this figure is taken very low compared with

practical experiments) it would be at the same time a saving of 3c. per

cubic meter water. If the cleaning of one cubic meter water therefore

costs less than 3c., this alone would be an advantage.

Already, for a long time, efforts have been made to find some means for

this purpose, and we have reached good results with lime and chloride of

barium, as well as with magnesia preparations. But these preparations

have many disadvantages. Corrosion of the boiler-iron and muriatic acid

gas have been detected. (Accounts of the Magdeburg Association for

boiler management.)

Chloride of calcium, which is formed by using chloride of barium,

increases the boiling point considerably, and diminishes the elasticity

of steam; while the sulphate of soda, resulting from the use of

carbonate of soda, is completely ineffectual against the boiler iron.

It increases the boiling point of water less than all other salts, and

diminishes likewise the elasticity of steam (Wullner).

In using magnesia preparation, the precipitation is only very slowly and

incompletely effected--one part of the magnesia will be covered by the

mire and the formed carbonate of magnesia in such a way, that it can no

more dissolve in water and have any effect (_Dingler's Polyt. Journal_,

1877-78).

The use of carbonate of soda is also cheaper than all other above

mentioned substances.

One milligramme equivalent sulphate of lime, in 1 liter, = 68 grammes

sulphate of lime in 1 cubic meter, requiring for decomposition:

120 gr. (86-88 per cent.) chloride of barium of commerce--at $5.00 =

0.6c.

Or, 50 gr. magnesia preparation--at $10.00 = 0.5c.

Or, 55 gr. (96-98 per cent.) carbonate of soda--at $7.50 = 0.41c.

The proportions of cost by using chloride of barium, magnesia

preparation, carbonate of soda, will be 6 : 5 : 4.

ARRANGEMENT FOR PURIFYING BOILER-WATER WITH LIME AND CARBONATE OF SODA.

We need for carrying out these manipulations, according to the size

of the establishment, one or more reservoirs for precipitating the

impurities of the water, and one pure water reservoir, to take up the

purified water; from the latter reservoir the boilers are fed. The most

practical idea would be to arrange the precipitating reservoir in such

manner that the purified water can flow directly into the feeding

reservoir.

The water in the precipitating reservoir is heated either by adding

boiling water or letting in steam up to 60 deg. C. at least. The

precipitating reservoirs (square iron vessels or horizontal

cylinders--old boilers) of no more than 4 or 41/2 feet, having a faucet 6

inches above the bottom, through which the purified water is drawn off,

and another one at the bottom of the vessel, to let the precipitate off

and allow of a perfect cleaning. In a factory with six or seven boilers

of the usual size, making together 400 square meters heating surface,

two precipitating reservoirs, of ten cubic meters each, and one pure

water reservoir of ten or fifteen cubic meter capacity, are used.

In twenty-four hours about 240 cubic meters of water are evaporated; we

have, therefore, to purify twenty-four precipitating reservoirs at ten

cubic meters each day, or ten cubic meters each hour.

It is profitable to surround the reservoirs with inferior conductors of

heat, to avoid losses.

The contents of the precipitating reservoirs have to be stirred up very

well, and for this purpose we can either arrange a mechanical stirrer

or do it by hand, or the best would be a "Korting steam stirring and

blowing apparatus." In using the latter we only have to open the valve,

whereby in a very short time the air driven through the water stirs this

up and mixes it thoroughly with the precipitating ingredients. In a

factory where boilers of only 15 to 100 square meters heating surface

are, one precipitating reservoir of two to ten cubic meters and one pure

water reservoir of three to ten cubic meters capacity are required. For

locomobiles, two wooden tubs or barrels are sufficient.

THE PURIFICATION OF THE WATER.

After the required quantity of lime and carbonate of soda which is

necessary for a total precipitation has been figured out from the

analysis of the water, respectively verified by practical experiments

in the laboratory, the heated water in the reservoir is mixed with the

lime, in form of thin milk of lime, and stirred up; we have to add so

much lime, that slightly reddened litmus paper gives, after 1/4 minute's

contact with this mixture, an alkaline reaction, i.e., turns blue; now

the solution of carbonate of soda is added and again stirred well.

After twenty or thirty minutes (the hotter the water, the quicker the

precipitation) the precipitate has settled in large flocks at the

bottom, and the clear water is drawn off into the pure water reservoir.

The precipitating and settling of the impurities can also take place in

cold water; it will require, however, a pretty long time.

In order to avoid the weighing and slaking of the lime, which is

necessary for each precipitation, we use an open barrel, in which a

known quantity of slaked lime is mixed with three and a half or four

times its weight of water, and then diluted to a thin paste, so that one

kilogramme slaked lime is diluted to twenty-five liters milk of lime.

Example.--If we use for ten cubic meters water, one kilogramme lime,

or in one day (in twenty-four hours), 240 cubic meters 24 kg. lime, a

vessel four or five feet high and about 700 liters capacity, in which

daily 24 kg. lime with about 100 liters water are slaked and then

diluted to the mark 600, constantly stirring, 25 liters of this mixture

contain exactly 1 kg. slaked lime.

Before using, this milk of lime has to be stirred up and allowed to

settle for a few seconds; and then we draw off the required quantity of

milk of lime (in our case 25 liters) through a faucet about 8 inches

above the bottom, or we can dip it off with a pail. For the first

precipitate we always need the exact amount of milk of lime, which we

have figured out, or rather some more, but for the next precipitates we

do not want the whole quantity, but always less, as that part of the

lime, which does not settle with the precipitate, will be good for use

in further precipitations. It is therefore important to control the

addition of milk of lime by the use of litmus paper. If we do not add

enough lime, it prevents the formation of the flocky precipitate, and,

besides, more carbonate of soda is used. By adding too much lime, we

also use more carbonate of soda in order to precipitate the excess of

lime. We can therefore add so much lime, that there is only a very small

excess of hydrous lime in the water, and that after well stirring, a red

litmus paper being placed in the water for twenty seconds, appears only

slightly blue. After a short time of practice, an attentive person can

always get the exact amount of lime which ought to be added. On adding

the milk of lime, we have to dissolve the required amount of pure

carbonate of soda in an iron kettle, in about six or eight parts hot

water with the assistance of steam; add this to the other liquid in the

precipitating reservoirs and stir up well. The water will get clear

after twenty-five or thirty minutes, and is then drawn off into the pure

water reservoir.

EXAMINATION OF WATER WHICH HAS BEEN PURIFIED BY MEANS OF MILK OF LIME

AND CARBONATE OF SODA.

In order to be convinced that the purification of the water has been

properly conducted, we try the water in the following manner. Take a

sample of the purified water into a small tumbler, and add a few

drops of a solution of oxalate of ammonia; this addition must neither

immediately nor after some minutes cause a milky appearance of the

water, but remain bright and clear. A white precipitate would indicate

that not enough carbonate of soda had been added. A new sample is taken

of the purified water and a solution of chloride of calcium added; a

milky appearance, especially after heating, would show that too much

carbonate of soda had been added.

RESULTS OF THIS WATER PURIFICATION.

1. The boilers do not need to be cleaned during a whole season, as they

remain entirely free from incrustation; it is only required to avoid a

collection of soluble salts in the boiler, and therefore it is partly

drawn off twice a week.

2. The iron is not touched by this purified water. The water does not

froth and does not stop up valves. The fillings in the joints of pipes,

etc., do not suffer so much, and therefore keep longer.

3. The steam is entirely free from sour gases.

4. The production of steam is easier and better.

5. A considerable saving of fuel can soon be perceived.

6. The cost of cleaning boilers from incrustation, and loss of time

caused by cleaning, is entirely done with. Old incrustations, which

could not be cleaned out before, get decomposed and break off in soft

pieces.

7. The cost of this purification is covered sufficiently by the above

advantages, and besides this, the method is cheaper and surer than any

other.

The chemical factory, Eisenbuettel, furnishes pure carbonate of soda in

single packages, which exactly correspond with the quantity, stated by

the analysis, of ten cubic meters of a certain water. The determination

of the quantities of lime and carbonate of soda necessary for a certain

kind of water, after sending in a sample, will be done without extra

charge.--_Neue Zeitung fur Ruebenzucker Industrie_.

* * * * *

EDDYSTONE LIGHTHOUSE.

The exterior work on the new Eddystone Lighthouse is about two thirds

done. In the latter part of April fifty-three courses of granite

masonry, rising to the height of seventy feet above high water, had been

laid, and thirty-six courses remained to be set. The old lighthouse had

been already overtopped. As the work advances toward completion the

question arises: What shall be done with John Smeaton's famous tower,

which has done such admirable service for 120 years? One proposition is

to take it down to the level of the top of the solid portion, and

leave the rest as a perpetual memorial of the great work which Smeaton

accomplished in the face of obstacles vastly greater than those which

confront the modern architect. The London _News_ says: "Were Smeaton's

beautiful tower to be literally consigned to the waves, we should regard

the act as a national calamity, not to say scandal; and, if public funds

are not available for its conservation, we trust that private zeal and

munificence may be relied on to save from destruction so interesting

a relic. It certainly could not cost much to convey the building in

sections to the mainland, and there, on some suitable spot, to re-erect

it as a national tribute to the genius of its great architect." When

the present lighthouse was built one of the chief difficulties was in

getting the building materials to the spot. They were conveyed from

Millbay in small sailing vessels, which often beat about for days before

they could effect a landing at the Eddystone rocks, so that each arrival

called out the special gratitude of Smeaton.

* * * * *

ROLLING-MILL FOR MAKING CORRUGATED IRON.

MESSRS. SCHULZ, KNAUDT & Co., of Essen, who are making an application

of corrugated iron in the construction of the interior flues of steam

boilers, have devised a new mill for the manufacture of this form of

iron plates, and which is represented in the accompanying cut, taken

from the _Deutsche Industrie Zeitung_. The supports of the two accessory

cylinders, F F, rest on two slides, G G, which move along the oblique

guides, H H. As a consequence of this arrangement, when the cylinders, F

F, are caused to approach the cylinder, D, both are raised at the same

instant.

When the cylinders, F, occupy the position represented in the engraving

by unbroken lines, the flat plate, O, is simply submitted to pressure

between the cylinders, D and P, the cylinders, F F, then merely acting

as guides. But when, while the plate is being thus flattened between the

principal cylinders, the accessory cylinders are caused to rise, the

plate is curved as shown by the dotted lines, O' O'. To obtain a

uniformity in the position of the two cylinders, F F, the following

mechanism is employed: Each cylinder has an axle, to which is affixed a

crank, Q, connected by means of a rod, R, with the slide, G. These axles

are also provided with toothed sectors, L L, which gear with two screws,

L L, whose threads run in opposite directions. These screws are mounted

on a shaft, N, which may be revolved by any suitable arrangement.

[Illustration: ROLLING MILL FOR MAKING CORRUGATED IRON]

* * * * *

RAILWAY TURN-TABLE IN THE TIME OF LOUIS XIV.

The small engraving which we reproduce herewith from _La Nature_ is

deposited at the Archives at Paris. It is catalogued in the documents

relating to Old Marly, 1714, under number 11,339, Vol. 1. The design

represents a diversion called the _Jeu de la Roulette_ which was

indulged in by the royal family at the sumptuous and magnificent chateau

of Mary-le-Roi.

[Illustration: PLEASURE CAR; RAILWAY AND TURN-TABLE OF THE TIME OF LOUIS

XIV.]

According to Alex. Guillaumot the apparatus consisted of a sort of

railway on which the car was moved by manual labor. In the car, which

was decorated with the royal colors, are seen seated the ladies and

children of the king's household, while the king himself stands in the

rear and seems to be directing operations. The remarkable peculiarity to

which we would direct the attention of the reader is that this document

shows that the car ran on rails very nearly like those used on the

railways of the present time, and that a turn-table served for changing

the direction to a right angle in order to place the car under the

shelter of a small building. The picture which we reproduce, and the

authenticity of which is certain, proves then that in the time of

Louis XIV. our present railway turn-tables had been thought of and

constructed--which is a historic fact worthy of being noted. It is well

known that the use of railways in mines is of very ancient date, but we

do not believe that there are on record any documents as precise as that

of the _Jeu de la Roulette_ as to the existence of turn-tables in former

ages.

* * * * *

NEW SIGNAL WIRE COMPENSATOR.

_To the Editor of the Scientific American_:

I send you a plate of my new railway signal wire compensator. Here

in India signal wires give more trouble, perhaps, than in America or

elsewhere, by expansion and contraction. What makes the difficulty more

here is the ignorance and indolence of the point and signalmen, who

are all natives. There have been numerous collisions, owing to signals

falling off by contraction. Many devices and systems have been tried,

but none have given the desired result. You will observe the signal wire

marked D is entirely separated and independent of the wire, E, leading

to lever. On the Great Indian and Peninsula Railway I work one of these

compensators, 1,160 yards from signal, which stands on a summit the

grade of which is 1 in 150; and on the Nizam State Railway I have one

working on a signal 800 yards. This signal had previously given so much

trouble that it was decided to do away with it altogether. It stands on

top of a high cutting and on a 1,600 foot curve.

[Illustration: Railway Signal Wire Comensator]

I have noted on the compensator fixed at 1,160 yards, 131/4 inches

contraction and expansion. The compensator is very simple and not at all

likely to get out of order. On new wire, when I fix my compensator, I

usually have an adjusting screw on the lead to lever. This I remove

when the wire has been stretched to its full tension. I have everything

removed from lever, so there can be no meddling or altering. When

once the wire is stretched so that no slack remains between lever and

trigger, no further adjustment is necessary.

A. LYLE,

Chief Maintenance Inspector, Permanent Way,

H.H. Nizam State Railway, E. India.

Secunderabad, India, 1881.

TANGYE'S HYDRAULIC HOIST.

[Illustration: TANGYE'S HYDRAULIC HOIST.]

The great merits of hydraulic hoists generally as regards safety and

readiness of control are too well known to need pointing out here.

We may, therefore, at once proceed to introduce to our readers the

apparatus of this class illustrated in the above engravings. This is

a hoist (Cherry's patent) manufactured by Messrs. Tangye Brothers, of

London and Birmingham, and which experience has proved to be a most

useful adjunct in warehouses, railway stations, hotels, and the like.

Fig. 1 of our engraving shows a perspective view of the hoist, Fig. 2

being a longitudinal section. It will be seen that this apparatus is of

very simple construction, the motion of the piston being transmitted

directly to the winding-drum shaft by means of a flexible steel rack.

Referring to Fig. 2, F is a piston working in the cylinder, G; E is

the flexible steel rack connected to the piston, F, and gearing with a

toothed wheel, B, which is inclosed in a watertight casing having cover,

D, for convenient access. The wheel, B, is keyed on a steel shaft, C,

which passes through stuffing-boxes in the casing, and has the winding

barrel, A, keyed on it outside the casing. H is a rectangular tube,

which guides the free end of the flexible steel rack, E. The hoist is

fitted with a stopping and starting valve, by means of which water

under pressure from any convenient source of supply may be admitted or

exhausted from the cylinder. The action in lifting is as follows: The

water pressure forces the piston toward the end of the cylinder. The

piston, by means of the flexible steel rack, causes the toothed wheel

to revolve. The winding barrel, being keyed on the same shaft as the

toothed wheel, also revolves, and winds up the weight by means of the

lifting chain. Two special advantages are obtained by this simple method

of construction. In the first place, twice the length of stroke can be

obtained in the same space as compared with the older types of hydraulic

hoist; and, from the directness of the action, the friction is reduced

to a minimum. This simple method of construction renders the hoist very

compact and easily fixed; and, from the directness with which the power

is conveyed from the piston to the winding drum, and the frictionless

nature of the mechanism, a smaller piston suffices than in the ordinary

hydraulic hoists, and a smaller quantity of water is required to work

them.--_Iron_.

* * * * *

POWER LOOM FOR DELICATE FABRICS.

The force with which the shuttle is thrown in an ordinary power

loom moving with a certain speed is always considerable, and, as a

consequence of the strain exerted on the thread, it is frequently

necessary to use a woof stronger than is desirable, in order that it may

have sufficient resistance. On another hand, when the woof must be very

fine and delicate the fabric is often advantageously woven on a hand

loom. In order to facilitate the manufacture of like tissues on the

power loom the celebrated Swiss manufacturer, Hanneger, has invented an

apparatus in which the shuttle is not thrown, but passed from one side

to the other by means of hooks, by a process analogous to weaving silk

by hand. A loom built on this principle was shown at work weaving silk

at the Paris Exhibition of 1878. This apparatus, represented in

the annexed figure, contains some arrangements which are new and

interesting. On each side of the woof in the heddle there is a carrier,

B. These carriers are provided with hooks, A A', having appendages,

_a a'_, which are fitted in the shuttle, O. The latter is of peculiar

construction. The upper ends of the hooks have fingers, _d d'_, which

holds the shuttle in position as long as the action of the springs, _e

e'_, continues. The distance that the shuttle has to travel includes the

breadth of the heddle, the length of the shuttle, and about four inches

in addition. The motion of the two carriers, which approach each other

and recede simultaneously, is effected by the levers, C, D, E, and C',

D', E'. The levers, E, E', are actuated by a piece, F, which receives

its motion from the main shaft, H, through the intervention of a

crank and a connecting rod, G, and makes a little more than a quarter

revolution. The levers, E, E', are articulated in such a way that

the motion transmitted by them is slackened toward the outer end and

quickened toward the middle of the loom. While the carriers, B B', are

receiving their alternate backward and forward motion, the shaft, I

(which revolves only half as fast as the main shaft), causes a lever, F

F', to swing, through the aid of a crank, J, and rod, K. Upon the two

carriers, B B', are firmly attached two hooks, M M', which move with

them. When the hook, M, approaches the extremity of the lever, F, the

latter raises it, pushes against the spring, E, and sets free the

shuttle, which, at the same moment, meets the opposite hook, _a'_, and,

being caught by it, is carried over to the other side. The same thing

happens when the carrier, B', is on its return travel, and the hook, M',

mounts the lever, F', which is then raised.

[Illustration: POWER LOOM FOR DELICATE FABRICS.]

As will be seen from this description, the woof does not undergo the

least strain, and may be drawn very gently from the shuttle. Neither

does this latter exert any friction on the chain, since it does not move

on it as in ordinary looms. In this apparatus, therefore, there may be

employed for the chain very delicate threads, which, in other looms,

would be injured by the shuttle passing over them. Looms constructed on

this plan have for some time been in very successful use in Switzerland.

* * * * *

HOW VENEERING IS MADE.

The process of manufacture is very interesting. The logs are delivered

in the mill yard in any suitable lengths as for ordinary lumber. A steam

drag saw cuts them into such lengths as may be required by the order

in hand; those being cut at the time of our visit were four feet long.

After cutting, the logs are placed in a large steam box, 15 feet wide,

22 feet long, and six feet high, built separate from the main building.

This box is divided into two compartments. When one is filled entirely

full, the doors are closed, and the steam, supplied by the engine in the

main building, is turned on. The logs remain in this box from three to

four hours, when they are ready for use. This steaming not only removes

the bark, but moistens and softens the entire log. From the steam box

the log goes to the veneer lathe. It is here raised, grasped at each end

by the lathe centers, and firmly held in position, beginning to slowly

revolve. Every turn brings it in contact with the knife, which is gauged

to a required thickness. As the log revolves the inequalities of its

surface of course first come in contact with the keen-edged knife, and

disappear in the shape of waste veneer, which is passed to the engine

room to be used as fuel. Soon, however, the unevenness of the log

disappears, and the now perfect veneer comes from beneath the knife in

a continuous sheet, and is received and passed on to the cutting table.

This continues until the log is reduced to about a seven inch core,

which is useless for the purpose. The veneer as it comes rolling off the

log presents all the diversity of colors and the beautiful grain and

rich marking that have perhaps for centuries been growing to perfection

in the silent depths of our great forests.

From the lathe, the veneer is passed to the cutting table, where it is

cut to lengths and widths as desired. It is then conveyed to the second

story, where it is placed in large dry rooms, air tight, except as the

air reaches them through the proper channels. The veneer is here placed

in crates, each piece separate and standing on edge. The hot air is then

turned on. This comes from the sheet iron furnace attached to the boiler

in the engine room below, and is conveyed through large pipes regulated

by dampers for putting on or taking off the heat. There is also a blower

attached which keeps the hot air in the dry rooms in constant motion,

the air as it cools passing off through an escape pipe in the roof,

while the freshly heated air takes its place from below. These rooms

are also provided with a net-work of hot air pipes near the floor. The

temperature is kept at about 165 deg., and so rapid is the drying process

that in the short space of four hours the green log from the steam box

is shaved, cut, dried, packed, and ready for shipment.

After leaving the dry rooms it is assorted, counted, and put up in

packages of one hundred each, and tied with cords like lath, when it is

ready for shipment. Bird's-eye maple veneer is much more valuable and

requires more care than almost any other, and this is packed in cases

instead of tied in bundles. The drying process is usually a slow one,

and conducted in open sheds simply exposed to the air. Mr. Densmore's

invention will revolutionize this process, and already gives his mill a

most decided advantage.

The mill will cut about 30,000 feet of veneer in a day, and this cut can

be increased to 40,000 if necessary. Mr. Densmore has already received

several large orders, and the rapidly increasing demand for this

material is likely to give the mill all the work it can do. The timber

used is principally curled and bird's-eye maple, beech, birch, cherry,

ash, and oak. These all grow in abundance in this vicinity, and the

beautifully marked and grained timber of our forests will find fitting

places in the ornamental uses these veneers will be put to.

* * * * *

THE CONSTITUENT PARTS OF LEATHER.

The constituent parts of leather seem to be but little understood. The

opinions of those engaged in the manufacture of leather differ widely on

this question.

Some think that tannin assimilates itself with the hide and becomes

fixed there by reason of a special affinity. Others regard the hide as

a chemical combination of gelatine and tannin. We know that the hide

contains some matters which are not ineradicable, but only need a slight

washing to detach them.

We deem it advisable, in order to examine the hide properly so-called,

to dispense with those eradicable substances which may be regarded, to

some extent, as not germain to it, and confine our attention to the raw

stock, freed from these imperfections.

It is well known that a large number of vegetable substances are

employed as tanning agents. Our researches have been directed to leather

tanned by means of the most important of these agents.

Many questions present themselves in the course of such an examination.

Among others, that most important one, from a practical point of view,

of the weight the tanning agent gives to the hide, that is to say, the

result in leather of weight given to the raw material. The degree of

tannage is also to be considered; the length of time during which the

tanning agent is to be left with the hide; in short, the influence upon

the leather of the substances used in its production. That is why we

have made the completest possible analysis of different leathers.

Besides ordinary oak bark there are used at present very different

substances, such as laurel, chestnut, hemlock, quebracho and pine bark,

sumac, etc.

Water is an element that exists in all hides, and it is necessary to

take it into consideration in the analysis. It is present in perceptible

quantity even in dry hides. This water cannot be entirely eradicated

without injuring the leather, which will lose in suppleness and

appearance. Water should then be considered as one of the elements of

leather, but it must be understood that if it exceeds certain limits,

say 12 to 14 per cent., it becomes useless and even injurious. Moreover,

if there is any excess over the normal quantity, it becomes deceptive

and dishonest, as in such a case one sells for hides that which is

nothing but water. Supposing that a hide, instead of only 14 per cent.,

contained 18 per cent. of water, it is evident that in buying 100 pounds

of such a hide one would pay for four pounds of water at the rate for

which he purchased the hide.

There are, also, some matters soluble in air, which are formed to a

large extent from fat arising as much from the hide as from tanning

substances. The air dissolves at the same time a certain amount of

organic acid and resinous products which the hide has absorbed. After

treating with air, alcohol is used, which dissolves principally the

coloring matters, tannin which has not become assimilated, bodies

analogous to resin, and some extractive substances.

That which remains after these methods have been pursued ought to be

regarded as the hide proper, that is to say, as the animal tissue

saturated with tannic acid. In this remainder one is able to estimate

with close precision that which belongs to the hide. The hide being an

elementary tissue of unchangeable form, it is easy, in determining the

elementary portion, to find the amount of real hide remaining in the

product. With these elements one can arrive at a solution of some of the

questions we are discussing.

We give below, according to this method, a table showing the composition

of the different leathers exhibited at the Paris Exposition of 1878.

They are the results of careful research, and we have based our work

upon them:

Matter Soluble Fixed

in Air Tannin

| |

| Matter Solu- |

| ble in Alcohol |

| | |

Moisture | | Gelatine |

--+-- --+-- --+-- --+-- --+--

Steer hide, hemlock tanned (heavy leather) 10.95 4.15 19.77 39.1 26.03

Sheepskins, sumac " (Hungarian) 10.8 10.3 12.1 40.3 26.5

Finished calf, pine bark tanned (Hungarian) 11.2 1.7 7.4 41.6 38.1

Steer hide, quebracho tanned (heavy leather) 11.7 1.6 11.2 43.1 32.4

" " chestnut " " " 13.5 0.29 1.99 45.46 38.76

Finished calfskins,

oak tanned (Chateau Renault) 12.4 0.33 3.59 46.74 36.94

Steer hide, laurel tanned (heavy leather) 12.4 1.05 7.95 47.47 31.13

" " oak tanned after three years in

the vats (heavy leather) 11.45 0.37 3.31 49.85 35.02

The following table shows the amount of leather produced by different

tannages of 100 pounds of hides:

Pounds.

Hemlock 255.7

Sumac 248.1

Pine 240.3

Quebracho 232

Chestnut 219.9

Oak 213.9

Laurel 210.6

Oak, lasting three years 206

It is important to mention here the large proportion of resinous matter

hemlock-tanned leather contains. This resin is a very beautiful red

substance, which communicates its peculiar color to the leather.

We should mention here that in these calculations we assume that the

hide is in a perfectly dry state, water being a changeable element which

does not allow one to arrive at a precise result.

These figures show the enormous differences resulting from diverse

methods of tanning. Hemlock, which threatens to flood the markets of

Europe, distinguishes itself above all. The high results attributable to

the large proportion of resin that the hide assimilates, explain in part

the lowness of its price, which renders it so formidable a competitor.

One is also surprised at the large return from sumac-tanned hides when

it is remembered in how short a time the tanning was accomplished,

which, in the present case, only occupied half an hour.

The figures show us that the greatest return is obtained by means of

those tanning substances which are richest in resin. In short, hemlock,

sumac, and pine, which give the greatest return, are those containing

the largest amount of resin. Thus, hemlock bark gives 10.58 per cent.

of it, and sumac leaves 22.7 per cent., besides the tannin which they

contain. We know also that pine bark is very rich in resin. There is,

then, advantage to the tanner, so far as the question of result is

concerned, in using these materials. There is, however, another side to

the question, as the leather thus surcharged with resin is of inferior

quality, generally has a lower commercial value, and is often of a color

but little esteemed.

The percentage of tannin absorbed by the different methods of tannages

appears in the following table:

Hemlock 64.2

Sumac 61.4

Pine 90.8

Quebracho 75.3

Chestnut 85.2

Oak 76.9

Laurel 64.8

Oak, three years in the vat 70.2

The subjoined is a statement of the gelatine and tannin in leather of

different tannages, and also shows the amount of azote or elementary

matter contained in each:

Gelatine. Tannin. Azote.

Hemlock 60.4 39.6 10.88

Sumac 60.4 39.6 11

Pine bark 52.5 47.5 9.56

Quebracho 57.1 42.9 10.4

Chestnut 53.97 46.03 9.79

Oak 55.87 44.13 10.24

Laurel 60.4 39.6 10.94

Oak, 3 years in vat 58.75 41.25 10.65

It is not pretended that these figures are absolutely correct, as they

often vary in certain limits even for similar products. They form,

however, a fair basis of calculation.

As to whether leather is a veritable combination, it seems to us that

this question should be answered affirmatively. In fact, the resistance

of leather properly so-called to neutral dissolvents, argues in favor of

this opinion.

Furthermore, the perceptible proportion of tannin remaining absorbed by

a like amount of hide is another powerful argument. It remains for us to

say here that the differences observable in the quantity of fixed tannin

ought to arise chiefly from the different natures of these tannins,

which have properties differing as do those of one plant from another,

and which really have but one property in common, that of assimilating

themselves with animal tissues and rendering them imputrescible.

In conclusion, these researches determine the functions of resinous

matters which frequently accompany tannin; they show a very simple

method for estimating the results of one's work, as well as the degree

of tannage.--_Muntz & Schoen, in La Halle aux Cuirs_.--_Shoe & Leather

Reporter_.

* * * * *

NEW HIGH SCHOOL FOR GIRLS, OXFORD.

The new High School for Girls at Oxford, built by Mr. T.G. Jackson, for

the Girls' Public Day School Company, Limited, was opened September 23,

1880, when the school was transferred from the temporary premises it had

occupied in St. Giles's. The new building stands in St. Giles's road,

East, to the north of Oxford, on land leased from University College,

and contains accommodation for about 270 pupils in 11 class-rooms, some

of which communicate by sliding doors, besides a residence for the

mistress, an office and waiting-room, a room for the teachers, cloak

rooms, kitchens, and other necessary offices, and a large hall, 50 ft.

by 30 ft., for the general assembling of the school together and for use

on speech-days and other public occasions. The principal front faces St.

Giles's road, and is shown in the accompanying illustration. The great

hall occupies the whole of the upper story of the front building, with

the office and cloak-rooms below it, and the principal entrance in the

center. The class-rooms are all placed in the rear of the building, to

secure quiet, and open on each floor into a corridor surrounding the

main staircase which occupies the center of the building. The walls

are built of Headington stone in rubble work, with dressings of brick,

between which the walling is plastered, and the front is enriched with

cornices and pilasters, and a hood over the entrance door, all of terra

cotta. The hinder part of the building is kept studiously simple and

plain on account of expense. Behind the school is a large playground,

which is provided with an asphalt tennis-court, and is picturesquely

shaded with apple-trees, the survivors of an old orchard. The builders

were Messrs. Symm & Co., of Oxford; and the terra cotta was made by

Messrs. Doulton, of Lambeth. Mr. E. Long was clerk of works.--_Building

News_.

[Illustration: SUGGESTIONS IN ARCHITECTURE--NEW HIGH SCHOOL, OXFORD]

* * * * *

PROGRESS IN AMERICAN POTTERY.

No advance in any industry has been more sure than in that of pottery

and chinaware, under the American tariff, or more rapid in the past

four or five years. It took Europe three centuries and the jealous

precautions of royal pottery proprietors to build up the great

protectorates that made their distinctive trade-marks of such value.

The earlier lusters of the Italian faience were guild privacies

or individual secrets, as was almost all the craft of the earlier

art-worker. Royal patronage in England was equivalent to a protective

tariff for Josiah Wedgwood; and everywhere the importance of guarding

the china nurseries has been understood. We have in this country

broadcast and in abundance every type of material needed for the

finest china ware, and for the finer glasses and enamels. The royal

manufactories in Europe were hard put to it sometimes for want of

discovering kaolin beds in their dominions, but the resources of the

United States in these particulars needed something more than to be

brought to light. The manipulation and washing of the clays to render

them immediately useful to the potteries depends entirely upon the

reliance of these establishments upon home materials. The Missouri

potteries have their supplies near home, but these supplies must be put

upon the market for other cities in condition to compete with the clays

of Europe. There are fine kaolin beds in Chester and Delaware counties

in this State; there are clay beds in New Jersey, and the recent needs

of Ohio potteries have uncovered fine clay in that State. This shows

that not only for the manufacture itself, but for the development of

material here, everything depends upon the stimulus that protection

gives.

Ohio china and Cincinnati pottery are known all over the country. The

Chelsea Works, near Boston, however, are as distinguished for their

clays and faience, and for lustrous tiles especially (to be used in

household decoration) can rival the rich show that the Doulton ware made

at the Centennial. Other New England potteries are eminent for terra

cotta and granite wares. On Long Island and in New York city there are

porcelain and terra cotta factories of established fame, and the first

porcelain work to succeed in home markets was made at the still busy

factories of Greenpoint. New Jersey potteries take the broad ground of

the useful, first of all, in their manufacture of excellent granite

and cream-colored ware for domestic use, but every year turn out more

beautiful forms and more artistic work. The Etruria Company especially

have succeeded in giving the warm flesh tints to the "Parian" for busts

and statuettes, now to be seen in many shop windows. These goods ought

always to be labeled and known as American--it adds to their value with

any true connoisseur. Some of these establishments, more than others,

have the enterprise to experiment in native clays, for which the whole

trade owes their acknowledgments.

The demand all through the country by skillful decorators for the

pottery forms to work upon, points to still greater extensions in this

business of making our own china, and to the employment and good pay of

more thousands than are now employed in it. A collection of American

china, terra cotta, etc., begun at this time and added to from year to

year, will soon be a most interesting cabinet. Both in the eastern

and western manufactories ingenious workers are rediscovering and

experimenting in pastes and glazes and colors, simply because there is a

large demand for all such, and they can be supplied at prices within the

reach of most buyers. It needs only to point out this flourishing state

of things, through the "let-alone" principle, which protection insures

to this industry, to exhibit the threatened damage of the attempt, under

cover of earthenware duties, to get a little free trade through at this

session.--_Philadelphia Public Ledger_.

* * * * *

PHOTOGRAPHIC NOTES.

_Mr. Warnerke's New Discovery_.--Very happily for our art, we are at the

present moment entering upon a stage of improvement which shows that

photography is advancing with vast strides toward a position that has

the possibility of a marvelous future. In England, especially, great

advances are being made. The recent experiments of our accomplished

colleague, Mr. Warnerke, on gelatine rendered insoluble by light, after

it has been sensitized by silver bromide and developed by pyrogallic

acid, have revealed to us a number of new facts whose valuable results

it is impossible at present to foretell. It seems, however, certain that

we shall thus be able to accomplish very nearly the same effects as

those obtained by bichromatized gelatine, but with the additional

advantage of a much greater rapidity in all the operations. In my own

experiments with the new process of phototypie, I hit upon the plan of

plunging the carbon image, from which all soluble gelatine had been

removed, into a bath of pyrogallic acid, in order to still further

render impermeable the substance forming the printing surface. I also

conceived the idea of afterward saturating this carbon image with a

solution of nitrate of silver, and of subsequently treating it with

pyrogallic acid, in order to still further render impermeable the

substance forming the printing surface. But the process described by Mr.

Warnerke is quite different; by means of it we shall be able to fix

the image taken in the camera, in the same way as we develop carbon

pictures, and afterward to employ them in any manner that may be

desirable. Thus the positive process of carbon printing would be

modified in such a manner that the mixtures containing the permanent

pigment should be sensitized with silver bromide in place of potassium

bichromate. In this way impressions could be very rapidly taken of

positive proofs, and enlargements made, which might be developed in hot

water, just as in the ordinary carbon process, and at least we should

have permanent images. Mr. Warnerke's highly interesting experiments

will no doubt open the way to many valuable applications, and will

realize a marked progress in the art of photography.

_Method for Converting Negatives Directly into Positives_.--Captain

Bing, who is employed in the topographic studios of the Ministry of

War, has devised a process for the direct conversion of negatives into

positives. The idea is not a new one; but several experimenters, and

notably the late Thomas Sutton, have pointed out the means of effecting

this conversion; it has never, however, so far as I know, been

introduced into actual practice, as is now the case. The process which

I am about to describe is now worked in the studios of the Topographic

Service. The negative image is developed in the ordinary way, but the

development is carried much further than if it were to be used as an

ordinary negative. After developing and thoroughly washing, the negative

is placed on a black cloth with the collodion side downward, and exposed

to diffuse light for a time, which varies from a few seconds to two or

three minutes, according to the intensity of the plate. Afterward the

conversion is effected by moistening the plate afresh, and then plunging

it into a bath which is thus composed:

Water 700 cub. cents.

Potassium bichromate 30 grams.

Pure nitric acid 300 cub. cents.

In a few minutes this solution will dissolve all the reduced silver

forming the negative; the negative image is therefore entirely

destroyed; but it has served to impress on the sensitive film beneath

it a positive image, which is still in a latent condition. It must,

therefore, be developed, and to do this, the film is treated with a

solution of--

Water 1,000 grams

Pyrogallic acid 25 "

Citric acid 20 "

Alcohol of 36 deg. 50 cub. cents.

The process is carried on exactly as if developing an ordinary negative;

but the action of the developer is stopped at the precise moment when

the positive has acquired intensity sufficient for the purpose for which

it is to be used. Fixing, varnishing, etc., are then carried on the

usual way. The great advantage of this process consists in the fact of

its rendering positives of much greater delicacy than those that are

taken by contact; and, on the other hand, by means of it we are able to

avoid two distinct operations, when for certain kinds of work we require

positive plates where a negative would be of no service. M. V. Rau,

the assistant who has carried out this process under the direction of

Captain Bing, has described it in a work which has just been published

by M. Gauthier-Villars.

_Experiments of Captain Bing on the Sensitiveness of Coal Oil_.--The

same Captain of Engineers has undertaken a series of very interesting

experiments on the sensitiveness to light of one or two substances to

which bitumen probably owes its sensitiveness, but which, contrary to

what takes place with bitumen, are capable of rendering very beautiful

half tones, both on polished zinc and on albumenized paper. These

sensitive substances are extracted by dissolving marine glue or coal-tar

in benzine. By exposure to light, both marine-glue and coal-tar turn of

a sepia color, and, in a printing-frame, they render a visible image,

which is not the case with bitumen; their solvents are in the order of

their energy; chloroform, ether, benzine, turpentine, petroleum spirit,

and alcohol. Of these solvents, benzine is the best adapted for reducing

the substances to a fluid state, so as to enable them to flow over the

zinc. The images obtained, which are permanent, and which are very much

like those of the Daguerreotype, are fixed by means of the turpentine

and petroleum spirit. They are washed with water, and then carefully

dried. It is possible to obtain prints with half-tones in fatty ink by

means of plates of zinc coated with marine-glue. Some attempts in this

direction were shown to me, which promised very well in this respect. We

are, therefore, in the right road, not only for economically producing

permanent prints on paper, but also for making zinc plates in which the

phototype film of bichromatized gelatine is replaced by a solution of

marine-glue and benzine. The substance known in commerce under the name

of pitch or coal-tar will produce the same results.

_Bitumen Plates_.--A new method of making bitumen plates by contact has

also been introduced into the topographical studios. The plan, or the

original drawing, is placed against a glass plate, coated with a mixture

of bitumen and of marine-glue dissolved in benzine. The marine-glue

gives the bitumen greater pliancy, and prevents it from scaling off when

rubbed, particularly when the plate is retouched with a dry point.

These bitumen plates are so thoroughly opaque to the penetration of the

actinic rays, that the printing-frame may be left for any time in full

sunlight without any fear of fog being produced on the zinc plate from

which the prints are to be taken.

_Method for Topographic Engraving by Commandant de la Noe_.--Before

leaving the interesting studios of which I have been speaking, I ought

to mention a very ingenious application which has been made of a process

called _topogravure_, invented by Commandant de la Noe, who is the

director of this important department. A plate of polished zinc is

coated with bitumen in the usual way, and then exposed directly to the

light under an original drawing, or even under a printed plan. So soon

as the light has sufficiently acted, which may be seen by means of

photometric bands equally transparent at the plate, all the bitumen not

acted upon is dissolved. As it is a positive which has acted as matrix,

the uncovered zinc indicates the design, and the ground remains coated

with insoluble bitumen. The plate is then etched with a weak solution

of nitric acid in water, and the lines of the design are thus slightly

engraved; the surface is then re-coated with another layer of bitumen,

which fills up all the hollows, and is then rubbed down with charcoal.

All the surface is thus cleaned off, and the only bitumen which remains

is that in the lines, which, though not deep, are sufficiently so to

protect the substance from the rubbing of the charcoal. When this

is done we have an engraved plate which can be printed from, like a

lithographic stone; it is gummed and wetted in the usual way, and it

gives prints of much greater delicacy and purity than those taken

directly from the bitumen. The ink is retained by the slight projection

of the surface beyond the line, so that it cannot spread, and a kind of

copper plate engraving is taken by lithographic printing. Besides, in

arriving at this result, there is the advantage of being able to use

directly the original plans and drawings, without being obliged to have

recourse to a plate taken in the camera; the latter is indispensable

for printing in the usual way on bitumen where the impression on the

sensitive film is obtained by means of a negative. It will be seen that

this process is exceedingly ingenious, and not only is its application

very easy, but all its details are essentially practical.

_Succinate of Iron Developer_.--I have received a letter from M.

Borlinetto, in which he states that he has been induced by the analogy

which exists between oxalic and succinic acids to try whether succinate

of iron can be substituted for oxalate of iron as a developer. To prove

this he prepared some proto-succinate of iron from the succinate of

potassium and proto-sulphate of iron, following the method given by Dr.

Eder for the preparation of his ferrous oxalate developer. He carried

out the development in the same way as is done by the oxalate, and

he found that the succinate of iron is even more energetic than the

oxalate. The plate develops regularly with much delicacy, and gives a

peculiar tone. It is necessary to take some fresh solution at every

operation, on account of the proto-succinate of iron being rapidly

converted into per-succinate by contact with the air.

_Method of Making Friable Hydro-Cellulose_.--At the meeting of the

Photographic Society of France, M. Girard showed his method of preparing

cellulose in a state of powder, specially adapted for the production of

pyroxyline for making collodion. Carded cotton-wool is placed in water,

acidulated with 3 per cent. of sulphuric or nitric acid, and is left

there from five to fifteen seconds; it is then taken out and laid on a

linen cloth, which is then wrung so as to extract most of the liquid. In

this condition there still remains from 30 to 40 per cent. of acidulated

water; the cotton is divided into parcels and allowed to dry in the open

air until it feels dry to the touch, though in this condition it still

contains 20 per cent. of water. It is next inclosed in a covered jar,

which is heated to a temperature of 65 deg. C.; the desiccation therefore

takes place in the closed space, and the conversion of the material

is completed in about two or three hours. In this way a very perfect

hydro-cellulose is obtained, and in the best form for producing

excellent pyroxyline.--_Corresp. Photo Mews_.

* * * * *

PHOTO TRACINGS IN BLACK AND COLOR.

Two new processes for taking photo tracings in black and color have

recently been published--"Nigrography" and "Anthrakotype"--both of which

represent a real advance in photographic art. By these two processes we

are enabled for the first time to accomplish the rapid production of

positive copies in black of plans and other line drawings. Each of

these new methods has its own sphere of action; both, therefore, should

deserve equally descriptive notices.

For large plans, drawn with lines of even breadth, and showing no

gradated lines, or such as shade into gray, the process styled

"nigrography," invented by Itterbeim, of Vienna, and patented both

in Germany and Austria, will be found best adapted. The base of this

process is a solution of gum, with which large sheets of paper can be

more readily coated than with one of gelatine; it is, therefore, very

suitable for the preparation of tracings of the largest size. The paper

used must be the best drawing paper, thoroughly sized, and on this the

solution, consisting of 25 parts of gum arabic dissolved in 100 parts of

water, to which are added 7 parts of potassium bichromate and I part of

alcohol, is spread with a broad, flat brush. It is then dried, and if

placed in a cool, dark place will keep good for a long time. When used,

it is placed under the plan to be reproduced, and exposed to diffused

light for from five to ten minutes--that is to say, to about 14 deg. of

Vogel's photometer; it is then removed and placed for twenty minutes in

cold water, in order to wash out all the chromated gum which has not

been affected by light. By pressing between two sheets of blotting-paper

the water is then got rid of, and if the exposure has been correctly

judged the drawing will appear as dull lines on a shiny ground. After

the paper has been completely dried it is ready for the black color.

This consists of 5 parts of shellac, 100 parts of alcohol, and 15 parts

of finely-powdered vine-black. A sponge is used to distribute the color

over the paper, and the latter is then laid in a 2 to 3 per cent. bath

of sulphuric acid, where it must remain until the black color can be

easily removed by means of a stiff brush. All the lines of the drawing

will then appear in black on a white ground. These nigrographic tracings

are very fine, but they only appear in complete perfection when the

original drawings are perfectly opaque. Half-tone lines, or the marks

of a red pencil on the original, are not reproduced in the nigrographic

copy.

"Anthrakotype" is a kind of dusting-on process. It was invented by Dr.

Sobacchi, in the year 1879, and has been lately more fully described by

Captain Pizzighelli. This process--called also "Photanthrakography"--is

founded on the property of chromated gelatine which has not been acted

on by light to swell up in lukewarm water, and to become tacky, so that

in this condition it can retain powdered color which had been dusted

on it. Wherever, however, the chromated gelatine has been acted on by

light, the surface becomes horny, undergoes no change in warm water, and

loses all sign of tackiness. In this process absolute opacity in

the lines of the original drawing is by no means necessary, for it

reproduces gray, half-tone lines just as well as it does black ones.

Pencil drawings can also be copied, and in this lies one great advantage

of the process over other photo-tracing methods, for, to a certain

extent, even half-tones can be produced.

For the paper for anthrakotype an ordinary strong, well-sized paper must

be selected. This must be coated with a gelatine solution (gelatine 1,

water 30 parts), either by floating the paper on the solution, or by

flowing the solution over the paper. In the latter case the paper is

softened by soaking in water, is then pressed on to a glass plate placed

in a horizontal position, the edges are turned up, and the gelatine

solution is poured into the trough thus formed. To sensitize the

paper, it is dipped for a couple of minutes in a solution of potassium

bichromate (1 in 25), then taken out and dried in the dark.

The paper is now placed beneath the drawing in a copying-frame, and

exposed for several minutes to the light; it is afterward laid in cold

water in order to remove all excess of chromate. A copy of the original

drawing now exists in relief on the swollen gelatine, and, in order to

make this relief sticky, the paper is next dipped for a short time in

water, at a temperature of about 28 deg. or 30 deg. C. It is then laid on a

smooth glass plate, superficially dried by means of blotting-paper, and

lamp-black or soot evenly dusted on over the whole surface by means of

a fine sieve. Although lamp-black is so inexpensive and so easily

obtained, as material it answers the present purpose better than any

other black coloring substance. If now the color be evenly distributed

with a broad brush, the whole surface of the paper will appear to be

thoroughly black. In order to fix the color on the tacky parts of the

gelatine, the paper must next be dried by artificial heat--say, by

placing it near a stove--and this has the advantage of still further

increasing the stickiness of the gelatine in the parts which have not

been acted upon by light, so that the coloring matter adheres even more

firmly to the gelatine. When the paper is thoroughly dry, place it in

water, and let it be played on by a strong jet; this removes all the

color from the parts which have been exposed to the light, and so

develops the picture. By a little gentle friction with a wet sponge, the

development will be materially promoted.

A highly interesting peculiarity of this anthrakotype process is the

fact that a copy, though it may have been incorrectly exposed, can

still be saved. For instance, if the image does not seem to be vigorous

enough, it can be intensified in the simplest way; it is only necessary

to soak the paper afresh, then dust on more color, etc.; in short,

repeat the developing process as above described. In difficult cases the

dusting-on may be repeated five or six times, till at last the desired

intensity is obtained.

By this process, therefore, we get a positive copy of a positive

original in black lines on a white ground. Of course, any other coloring

material in a state of powder may be used instead of soot, and then a

colored drawing on a white ground is obtained. Very pretty variations of

the process may be made by using gold or silver paper, and dusting-on

with different colors; or a picture may be taken in gold bronze powder

on a white ground. In this way colored drawings may be taken on a gold

or a silver ground, and very bright photo tracings will be the result.

Some examples of this kind, that have been sent us from Vienna, are

exceedingly beautiful.

Summing up the respective advantages of the two processes we have above

described, we may say that "nigrography" is best adapted for

copying drawings of a large size; the copies can with difficulty be

distinguished from good autographs, and they do not possess the bad

quality of gelatine papers--the tendency to roll up and crack. Drawings,

however, which have shadow or gradated lines cannot be well produced by

this process; in such cases it is better to adopt "anthrakotype," with

which good results will be obtained.--_Photographic News_.

* * * * *

ON M. C. FAURE'S SECONDARY BATTERY.

The researches of M. Gaston Plante on the polarization of voltameters

led to his invention of the secondary cell, composed of two strips of

lead immersed in acidulated water. These cells accumulate, and, so to

speak, store up the electricity passed into them from some outside

generator. When the two electrodes are connected with any source of

electricity the surfaces of the two strips of lead undergo certain

modifications. Thus, the positive pole retains oxygen and becomes

covered with a thin coating of peroxide of lead, while the negative pole

becomes reduced to a clean metallic state.

Now, if the secondary cell is separated from the primary one, we have a

veritable voltaic battery, for the symmetry of the poles is upset, and

one is ready to give up oxygen and the other eager to receive it. When

the poles are connected, an intense electric current is obtained, but

it is of short duration. Such a cell, having half a square meter of

surface, can store up enough electricity to keep a platinum wire 1

millim. in diameter and 8 centims. long, red-hot for ten minutes. M.

Plante has succeeded in increasing the duration of the current by

alternately charging and discharging the cell, so as alternately to

form layers of reduced metal and peroxide of lead on the surface of the

strip. It was seen that this cell would afford an excellent means for

the conveyance of electricity from place to place, the great drawback,

however, being that the storing capacity was not sufficient as compared

with the weight and size of the cell. This difficulty has now been

overcome by M. Faure; the cell as he has improved it is made in the

following manner:

The two strips of lead are separately covered with minium or some other

insoluble oxide of lead, then covered with an envelope of felt, firmly

attached by rivets of lead. These two electrodes are then placed near

each other in water acidulated with sulphuric acid, as in the Plante

cell. The cell is then attached to a battery so as to allow a current

of electricity to pass through it, and the minium is thereby reduced to

metallic spongy lead on the negative pole, and oxidized to peroxide of

lead on the positive pole; when the cell is discharged the reduced lead

becomes oxidized, and the peroxide of lead is reduced until the cell

becomes inert.

The improvement consists, as will be seen, in substituting for strips

of lead masses of spongy lead; for, in the Plante cell, the action is

restricted to the surface, while in Faure's modification the action is

almost unlimited. A battery composed of Faure's cells, and weighing 150

lb., is capable of storing up a quantity of electricity equivalent to

one horsepower during one hour, and calculations based on facts in

thermal chemistry show that this weight could be greatly decreased. A

battery of 24 cells, each weighing 14 lb., will keep a strip of platinum

five-eighths of an inch wide, one-thirty-second of an inch thick, and 9

ft. 10 in. long, red-hot for a long time.

The loss resulting from the charging and discharging of this battery is

not great; for example, if a certain quantity of energy is expended in

charging the cells, 80 per cent. of that energy can be reproduced by the

electricity resulting from the discharge of the cells; moreover, the

battery can be carried from one place to another without injury. A

battery was lately charged in Paris, then taken to Brussels, where it

was used the next day without recharging. The cost is also said to be

very low. A quantity of electricity equal to one horse power during an

hour can be produced, stored, and delivered at any distance within 3

miles of the works for 11/2d. Therefore these batteries may become useful

in producing the electric light in private houses. A 1,250 horsepower

engine, working dynamo-machines giving a continuous current, will in one

hour produce 1,000 horse-power of effective electricity, that is to

say 80 per cent. of the initial force. The cost of the machines,

establishment, and construction will not be more than L40,000, and the

quantity of coal burnt will be 2 lb. per hour per effective horse-power,

which will cost (say) 1/2d. The apparatus necessary to store up the force

of 1,000 horses for twenty-four hours will cost L48,000, and will weigh

1,500 tons. This price and these weights may become much less after a

time. The expense for wages and repairs will be less than 1/4d. per hour

per horse-power, which would be L24 a day, or L8,800 a year; thus the

total cost of one horse-power for an hour stored up at the works is

3/4d. Allowing that the carriage will cost as much as the production and

storing, we have what is stated above, viz., that the total cost within

3 miles of the works is 11/2d. per horse-power per hour. This quantity of

electricity will produce a light, according to the amount of division,

equivalent to from 5 to 30 gas burners, which is much cheaper than

gas.--_Chemical News_.

* * * * *

PHYSICAL SCIENCE IN OUR COMMON SCHOOLS.

[Footnote: Read before the State Normal Institute at Winona, Minnesota,

April 28, 1881, by Clarence M. Boutelle, Professor of Mathematics and

Physical Science in the State Normal School.]

Very little, perhaps, which is new can be said regarding the teaching

of physical science by the experimental method. Special schools for

scientific education, with large and costly laboratories, are by no

means few nor poorly attended; scientific books and periodicals are

widely read; scientific lectures are popular. But, while in many schools

of advanced grade, science is taught in a scientific way, in many others

the work is confined to the mere study of books, and in only a few of

our common district schools is it taught at all.

I shall advocate, and I believe with good reason, the use of apparatus

and experiments to supplement the knowledge gained from books in schools

where books are used, the giving of lessons to younger children who do

not use books, and the giving of these lessons to some extent in all

our schools. And the facts which I have gathered together regarding the

teaching of science will be used with all these ends in view.

Physics--using the term in its broadest sense--has been defined as the

science which has for its object the study of the material world, the

phenomena which it presents to us, the laws which govern (or account

for) these phenomena, and the applications which can be made of either

classes of related phenomena, or of laws, to the wants of man. Thus

broadly defined, physics would be one of two great subjects covering the

whole domain of knowledge. The entire world of matter, as distinguished

from the world of mind, would be presented to us in a comprehensive

study of physics.

I shall consider in this discussion only a limited part of this great

subject. Phenomena modified by the action of the vital force, either in

plants or in animals, will be excluded; I shall not, therefore, consider

such subjects as botany or zooelogy. Geology and related branches will

also be omitted by restricting our study to phenomena which take place

in short, definite, measurable periods of time. And lastly, those

subjects in which, as in astronomy, the phenomena take place beyond

the control of student and teacher, and in which their repetition at

pleasure is impossible, will not be considered. Natural philosophy, or

physics, as this term is generally used, and chemistry, will, therefore,

be the subjects which we will consider as sources from which to draw

matter for lessons for the children in our schools.

The child's mind has the receptive side, the sensibility, the most

prominent. His senses are alert. He handles and examines objects about

him. He sees more, and he learns more from the seeing, than he will in

later years unless his perceptive powers are definitely trained and

observation made a habit. His judgment and his will are weak. He reasons

imperfectly. He chooses without appropriate motives. He needs the

building up and development given by educational training. _Nature

points out the method._

Sensibility being the characteristic of his mind, we must appeal to him

through his senses. We must use the concrete; through it we must act

upon his weak will and immature judgment. From his natural curiosity we

must develop attention. His naturally strong perceptive powers must be

made yet stronger; they must be led in proper directions and fixed upon

appropriate objects. He must be led to appreciate the relation between

cause and effects--to associate together related facts--and to state

what he knows in a definite, clear, and forcible manner.

Object lessons, conversational lessons, lessons on animals, lessons

based on pictures and other devices, have been used to meet this demand

of the child's mental make up. Good in many respects, and vastly better

than mere book work, they have faults which I shall point out in

connection with the corresponding advantages of easy lessons in the

elements of science. I shall not quibble over definitions. Object

lessons may, perhaps, properly be said to include lessons such as it

seems to me should be given--lessons drawn from natural philosophy or

chemistry--but I use the term here in the sense in which it is often

used, as meaning lessons based upon some object. A thimble, a knife, a

watch, for instance, each of these being a favorite with a certain class

of object teachers, may be taken.

The objections are:

1. Little new knowledge can be given which is simple and appropriate.

Most children already know the names of such objects as are chosen,

the names of the most prominent parts, the materials of which they are

composed and their uses. Much that is often given should be omitted

altogether if we fairly regard the economy of the child's time and

mental strength. It doesn't pay to teach children that which isn't worth

remembering, and which we don't care to have them remember.

2. Study of the qualities of materials is a prominent part of lessons on

objects. Such study is really the study of physical science, but with

objects such as are usually selected is a very difficult part to give

to young children. Ask the student who has taken a course in chemistry

whether the study of the qualities of metals and their alloys is easy

work. Ask him how much can readily be shown, and how much must be taken

on authority. Have him tell you how much or how little the thing itself

suggests, and how much must he memorized from the mere book statement

and with difficulty. Study of materials is good to a certain extent, but

it is often carried much too far.

Consider a conversational lesson on some animal. Lessons are sometimes

given on cats. As an element in a reading lesson--to arouse interest--to

hold the attention--to secure correct emphasis and inflection--to make

sure of the reading being good: such work is appropriate. But let us see

what the effect upon the pupil is as regards the knowledge he gains

of the cat, and the effect upon his habits of thought and study. The

student gives some statement as to the appearance--the size--or some

act of his cat. It is usually an imperfect statement drawn from the

imperfect memory of an imperfect observation. And the teacher, having

only a _general knowledge_ of the habits of cats, can correct in only

a general way. Thus habits of faulty and incorrect observation and

inaccurate memory are fastened upon the child. It is no less by the

correction of the false than by the presenting of the true, that we

educate properly.

Besides this there is the fact that traits, habits, and peculiarities

of animals are not always manifested when we wish them to be. Suppose

a teacher asks a child to notice the way in which a dog drinks, for

example; the child may have to wait until long after all the associated

facts, the reasons why this thing was to be observed--the lesson as a

whole of which this formed a part--have all grown dim in the memory,

before the chance for the observation occurs.

Pictures are less valuable as educational aids than objects; at best

they are but partially and imperfectly concrete. The study of pictures

tends to cultivate the imagination and taste, but observation and

judgment are but little exercised.

A comparison of the kind of knowledge gained in either of the above ways

with that gained by a study of science as such, will make some of the

advantages of the latter evident. An act of complete knowledge consists

in the identifying of an attribute with a subject. Attributes of

quality--of condition--of relation, may be gained from lessons in which

objects or pictures are used. Attributes of action which are unregulated

by the observer may be learned from the study of animals. But very

little of actions and changes which can be made to take place under

specified conditions, and with uniformity of result, can be learned

until physical science is drawn upon.

And yet consider the importance of such study. Changes around him appeal

most strongly to the child. "Why _does_ this thing _do_ as it _does_?"

is more frequent than "Why _is_ this thing as it _is_?" He sees changes

of place, of form, of size, of composition, taking place; his curiosity

is aroused; and he is ready to study with avidity, and in a systematic

manner, the changes which his teacher may present to him. Consider

the peculiarities belonging to the study of changes of any sort. The

interest is held, for the mind is constantly gaining the new. The

attention cannot be divided--all parts of the change, all phases of the

action, must be known, and to be known must be _observed_; while in

other forms of lessons the attention may be diverted for a moment to

return to the consideration of exactly what was being observed before.

It goes without saying that in one case quick and accurate observation,

a retentive memory, and the association of causes and effects follow,

and that in the other they do not.

I advocate, therefore, the teaching of physical science in our

schools--_in all our schools_. Physical science taught by the

experimental method.

An experiment has been defined as a question put to Nature, a question

asked in _things_ rather than in _words_, and so conditioned that no

uncertain answer can be given. Nature says that all matter gravitates,

not in words, but in the swing of planets around the sun, and in the

leap of the avalanche. And men have devised ingenious machines through

which Nature may tell us the invariable laws of gravitation, and give

some hint as to why it is true.

There are two kinds of experiments, and two corresponding kinds of

investigators.

I. In original investigation there are the following elements:

1. The careful determination of all the conditions under which the

experiment takes place.

2. The observation of exactly what happens, with a painstaking

elimination of all previous notions as to what ought to happen.

3. The change of conditions, one at a time, with a comparison of the

results obtained with the changes made, in order to determine that each

condition has been given just its appropriate weight in the experiment.

4. The classification and explanation of the result.

5. The extension of the knowledge gained by turning it to investigations

suggested by what has already been learned.

6. The practical application of the knowledge gained.

II. In ordinary experiments for educational purposes the experimenter

follows in a general way in the footsteps of the original investigator.

There are the following elements to be considered:

1. The arrangement of conditions in general imitation of the original

investigator. This arrangement needs only to be general. For example, if

an original investigation were undertaken to determine the composition

of a metallic oxide, the metal and the oxygen would both be carefully

saved to be measured and weighed and fully tested. The ordinary

experiment would be considered successful if oxygen and the metal were

shown to result.

2. The careful consideration of what should happen.

3 The determination that the expected either does or does not happen,

with examination of reasons and elimination of disturbing causes in the

latter case.

4. The accepting as true of the classification and explanation already

given. Theories, explanations, and laws are thus accepted every day by

minds which could never have originated either them or the experiments

from which they were derived.

The method of original investigation, strictly considered, presents

many difficulties. A long course of preliminary training--a thorough

knowledge of what has been done in a given field already--a quick

imagination--a genius for devising forms of apparatus which will enable

him to work well under particular conditions in the most simple and

effective way--the faculty of suspending judgment, and of seeing

what happens, all that happens, and just how it

happens--patience--caution--courage--quick judgment when a completed

experiment presses for an explanation--these are some of the

characteristics which must belong to the original worker.

Were we all capable of doing such work there would be these advantages,

among others, of studying for ourselves:

1. What we find out for ourselves we remember longer and recall more

readily than what we acquire in any other way. This advantage holds true

whether the facts learned are entirely new or only new to us. Almost

every man whose life has been spent in study has a store of facts which

he discovered, and on which he built hopes of future greatness until

he found out later that they were old to the knowledge of the world he

lived in. And these things are among those which will remain longest in

his memory.

2. Associated facts would be learned in studying in this way which would

remain unknown otherwise.

But all the advantages would be associated with disadvantages too. Long

periods of time would have to be given for comparatively small results.

The history of science is full of instances in which years were spent in

the elaboration of some law, or principle, or theory which the school

boy of to-day learns in an hour and recites in a breath. Why does water

rise in a pump? Do all bodies, large and small, fall equally fast? The

principles which answer and explain such questions can be made so clear

and evident to the mind of a pupil that he would almost fancy they must

have been known from the first instead of having waited for the hard,

earnest labor of intellectual giants. And science has gone on, and

for us and for our pupils would still go on, only as accompanied with

numerous mistakes and disappointments.

What method shall we adopt in the teaching of science? It must

differ according to the age and capacity of the pupils. An excellent

modification of the method of original investigation may be arranged as

follows:

The children are put in possession of all facts relating to conditions,

the teacher explaining them as much as may be necessary. The experiment

is performed, the pupils being required to observe exactly what takes

place, the experiments selected being of such a nature that any previous

judgment as to what ought to occur is as nearly impossible as may be. We

predict from knowledge, real or supposed, of facts which are associated

in our minds with any new subject under consideration. Children often

know in a general, vague, and indefinite way that which, for the sake of

a full and systematic knowledge, we may desire them to study. What

they know will unconsciously modify their expectations, and their

expectations in turn may modify their observations. We are apt to

believe that happens which we expect will happen. There ought to be no

difficulty, however, in finding simple and appropriate experiments with

which the child is entirely unacquainted, and in which anything beyond

the wildest guess work is, for him, impossible. The principal use which

can be made of this method is in the mere observation of what takes

place. Nothing which the child notices correctly need be rejected,

no matter how far removed from the chief event on the object of the

experiment. Care that the pupil shall see all, and separate the

essential from the accidental, is all that is necessary.

But the original investigator assigns reasons, and with care the

children may be allowed to attempt that. This, however, should not be

carried far; incorrect explanations should be criticised; and the class

should at length be given all the elements of the correct explanation

which they have not determined for themselves. Later, pupils should be

encouraged to name related phenomena, to mention things which they

have seen happen which are due to associated causes, and to suggest

variations for the experiment and tests for its explanation. Good

results may be made to follow this kind of work even with very young

pupils. A child grows in mental strength by using the powers he has, and

mistakes seen to be such are not only steps toward a correct view of the

subject under consideration, but are steps toward that habit of mind

which spontaneously presents correct views at once in study which comes

later in life.

Another method is this: The pupil may know what is expected to happen,

as well as the conditions given, and held responsible for an observation

of what does happen and a comparison of what he really observes with

what he expects to observe. Explanations are usually given a class,

often in books with which they are furnished, instead of being drawn

from them, in whole or in part, by questioning, when physical science is

studied in this way. Indeed, this method is a necessity when text books

are used, unless experiments from some outside source are introduced.

Who shall perform the experiments? With young pupils everywhere, and

in most of our common, and even in many of our graded schools, the

experiments must be performed by the teacher. With young pupils the time

is too limited, and the responsibility and necessary care too great to

permit of any other plan being practical. In many of our schools the

small supply of apparatus renders this necessary even with larger

pupils. Added to the reasons already given is the important one that in

no other way--by no other plan--can the teacher be as readily sure that

his pupils observe and reason fully for themselves. In this normal

school a course in physics, in which the experiments are all performed

in the class room by the teacher, is followed by a course in chemistry,

in which the members of the class perform the experiments for themselves

in the laboratory. And, notwithstanding the age, maturity, and previous

observation of the pupils, a great deal must be done both in the

laboratory and in the recitation room to be sure that all that happens

is seen--that the purpose is clearly held in the mind--that the reason

is fully understood.

With older pupils and greater facilities, however, the experiments

should be performed by the pupils themselves. Constant watchfulness is

necessary, it is true, to insure to the pupil the full educational

value of the experiment. With this watchfulness it can be done, and the

advantages are numerous. Among them are:

1. The learning of the use and care of apparatus.

2. The learning of methods of actual construction, from materials at

hand, of some of the simpler kinds of apparatus.

3. The learning of the importance of careful preparation. An experiment

may be performed in a few minutes before a class which has taken an hour

or more of time in its preparation. The pupil fully appreciates its

importance, and is in the best condition to remember it only when he

has had a part of the hard work attending that preparation. Again,

conditions under which an experiment is successfully performed are often

not appreciated when merely stated in words. "To prepare hydrogen gas,

pass a thistle tube and a delivery tube through a cork which fit tightly

in the neck of a bottle," etc., is simple enough. Let a pupil try with a

cork which does not fit tightly and he will never forget that condition.

4. The learning of the importance of following directions. Chemistry,

especially, is full of those cases where this means everything.

Sometimes, not often in experiments performed in school, however, it may

mean even life or death.

The time for experiments should be carefully considered. When performed

by the teacher they should be taken up during the recitation:

1. If used as a foundation to build upon, at the beginning of the

lesson.

2. If used as a summary, at the close.

3. They should be closely connected with the points which they

illustrate.

4. When very short, or when so difficult as to demand the whole

attention of the teacher, they may be given and afterward discussed. If

long or easy, they may be discussed while the work is going on. Changes

which take place slowly, as those which are brought about by the gradual

action of heat, for instance, are best taken up in this latter way.

5. Exceptions may be necessary, as when experiments which demand special

preparation immediately before they are presented are given when the

recitation begins, or cases in which experiments are kept until near the

close of a recitation, when the teacher finds that attention flags and

the lesson seems to have lost its interest to the pupils as soon as the

experiments have been given.

When performed by the pupils themselves, experiments should come before

the recitation as a part of the preparation for the work of the class

room.

Even in those cases in which the teacher performs the work, opportunity

should be given, from time to time, for the performing of the experiment

by the pupils themselves. This can be done in several ways. During the

course in physics here I am in the habit of leaving apparatus on the

table in my room for at least one day, often for a longer time, and of

giving permission to my class to perform the experiments for themselves

when their time permits and the nature of the experiment makes it an

advantage to get a nearer view than was possible in the class work. I

leave it to them to decide when to perform the experiments, or whether

it is to their advantage to take the time to perform them at all. I make

no attempt to watch either pupils or apparatus, although I would

often assist or explain at intermissions or during the afternoon. The

apparatus was largely used, and the effect on recitations was a good

one. For advanced pupils, and those who can be fully trusted, the plan

is a good one. The only question is the safety of the apparatus; each

teacher can decide for himself regarding the advisability of the plan

for his own school.

With smaller pupils their own safety may render it best to keep

apparatus out of their hands, except under the immediate direction of

the teacher. With all pupils that is, doubtless, the best plan where

chemicals are concerned.

Another method is to allow pupils to assist the teacher in the

preparation of experiments, to call occasionally upon members of the

class to come forward and give the experiment in the place of the

teacher, and to encourage home work relating to experiments. This latter

is often spontaneous on the part of older pupils, and can be brought

about with the smaller ones by the use of a little tact; many of the

toys of the present day have some scientific principle at bottom; let

the teacher find out what toys his young pupils have, and encourage them

to use them in a scientific way.

In whatever ways experiments be used, the class should be made to

consider the following elements as important in every case:

1. The purpose of the experiment. The same experiment may be performed

at one time for one purpose, at another time for another. The purpose

intended should be made the prominent thing, all others being

subordinated to it. Many chemical reactions, for instance, can be made

to yield either one of two or more substances for study or examination,

or use, while it may be the purpose of the experiment to close only one

of them.

2 The apparatus. All elements should be considered. The necessary should

be separated from that which may vary. In cases where the various parts

must have some definite relation to the others as regards size or

position, all that should be considered with care. In complex apparatus

the exact office of each part should be understood.

3. A clear understanding of what happens. To this I have already

referred.

4. Why it happens.

5. In what other way it might be made to happen. In chemistry almost

every substance can be prepared in several different ways. The common

method is in most cases made so by some consideration of convenience,

cheapness, or safety. Often only one method is considered in one place

in a text book. In a review, however, several methods can be associated

together. Tests, uses, etc., will vary, too, and should be studied with

that fact in view. In physics phenomena illustrating a given principle

can usually be made to take place in several different ways. Often very

simple apparatus will do to illustrate some fact for which complex and

costly apparatus would be convenient. In such case the study of the

experiment with that fact in view becomes important to us who need to

simplify apparatus as much as possible.

6. Special precautions which may be necessary. Some experiments always

work well, even in the hands of those not used to the work. Others are

successful--sometimes safe, even--only when the greatest care is taken.

Substances are used constantly in work in chemistry which are deadly

poisons, others which are gaseous and will pass through the smallest

holes. In physics the experiments usually present fewer difficulties of

this sort. But special care is necessary to complete success here.

7. Other things shown by the experiment. While the main object should

be kept in most prominent view in all experimental work, the fullest

educational value will come only when all that can be learned by the use

of an experiment is carefully considered.

In selecting just the work to be taken up with a given class of

children, attention must be paid to the selection of the appropriate

matter to be presented and the well adapted method of presenting it. The

following points should be carefully considered:

1. The matter must be adapted to the capacity of the child. This must be

true both as regards the quality and the quantity. The tendency will be

to teach too much when the matter presented is entirely new, but too

little in many cases where the pupil already knows the subject in a

general way. Matter is valuable only when given slowly enough to permit

of its being fully understood and memorized, while on the other hand

method is valuable only when it secures the development of attention and

the various faculties of the child's mind by presenting a sufficient

amount of the new.

2. The work must be based on what is already known. This, one of the

best known of the principles of teaching, is of at least as great

importance in physical science as in any other department of knowledge.

It seems to me in many cases to be more important here than elsewhere.

It is not necessary to reach each point by passing over every other

point usually considered. Lessons in electricity or sound, for instance,

can be given to children who have done nothing with other parts of

science. But a natural beginning must be made, and an orderly sequence

of lessons adopted. Children will not do what adults would find almost

impossible in covering gaps between lessons.

Science may be compared to a great temple. Pillars, each built of many

curiously joined stones, standing at the very entrance, represent the

departments of science so far as man has studied them. We need not dig

down and study the foundations with the children; we need not study

every pillar nor choose any particular one rather than some other; but

we must learn something of every stone--of each great fact--in the

pillar we select, be it ever so little. The original investigator climbs

to stones never before reached, or boldly ventures away into the dim

recesses beyond the entrance to bring back hints of what may be known

and believed a hundred years hence, perhaps. The exact investigator

measures each stone. Patiently and toilsomely scientific men examine

them with glass and reagent. We need not do this, but we must omit none

of the stones.

3. The work must be continuous. To continue the figure, the stones must

be considered in some regular order. One lesson in electricity, one in

sound, then one in some other department is injurious. We remember best

by associated facts, and, while with the child this is less so than with

the man, one great object of this work is to teach him to remember in

that way.

4. Experiments should never be performed for mere show. Of two

experiments which illustrate a fact equally well it is often best to

select the most striking and brilliant one. The attention and interest

of the child will be gained in this way when they would not be to so

great an extent in any other. The point of the experiment, however,

should never be lost sight of in attention to the merely wonderful in

it.

With older pupils, and especially with those who use books for

themselves and perform the experiments there considered, the fact that

experiments demand work, downright hard work, with care, and patience,

and perseverance, and courage, cannot be kept too prominently before

them.

5. Every lesson should have a definite object. Not the general value of

the experiment, but some _one thing_ which it shows should be the object

considered.

6. Each experiment should be associated with some truth expressed in

words. The experiment should be remembered in connection with a definite

statement in each case. The memory of either the experiment, or the

principle apart from the experiment, is a species of half knowledge

which should be avoided. An unillustrated principle must, when the

necessity arises, be stored in the memory; and in the systematic study

of books this necessity will often come. But we should never crowd this

abstract work on the memory unassisted by the suggestive concrete, when

the concrete aid is possible.

7. All that is taught should be true. It is not necessary to attempt to

exhaust a subject, nor to attempt to teach minute details regarding it

to the pupils in our schools, but it is necessary that every statement

given to the pupil to be learned and remembered should contain no

element of falsehood.

The student in mathematics experiences a feeling of growing strength and

power when he finds, in algebra, that the formula he used in arithmetic

in extracting a square root has grown in importance by leading

indirectly to a theorem of which it is only one particular case--a

theorem with a more definite proof, and a larger capability for use than

he had thought possible. When he finds a still simpler proof for the

binomial theorem in his study of the calculus, his feeling of increasing

power and the desire for still greater results deepens and intensifies.

Were he to find, on the contrary, that from a false notion of the means

to be used in making a thing simple, his teacher in arithmetic had

taught him what is false, we should approve his feeling of disgust and

disappointment. Early impressions are the most lasting, and the hardest

part of school work for the teacher is the unteaching of false ideas,

and the correcting of imperfectly formed and partially understood ideas.

I took a case from mathematics, the exact science, to illustrate this

point. But I must not neglect to notice the difference between that

subject and physical science. The latter consists of theories,

hypotheses, and so-called laws, supported by _observed facts_. The facts

remain, but time has overthrown many of the hypotheses and theories, and

it will doubtless overthrow more and give us something better and truer

in their place. While a careful distinction between what is known and

what is believed is necessary, I should always class the teaching of

accepted theories and hypotheses with the teaching of the true.

But teachers, with more of imagination than good sense, teach

distinctions which do not exist, generalizations which do not

generalize, and do incalculable mischief by so doing.

8. Experimental work should be thoroughly honest as to conditions and

results. If an experiment is not the success you expected it would be,

say so honestly, and if you know why, explain it. The pupil should be

taught to know just what _is_, theory or expectation to the contrary

notwithstanding. Discoveries in physical science have often originated

in a search for the reason for some unexpected thing.

The relation of the study of science to books on science should be

considered. For the work done with pupils before they are given books to

use for themselves, any attempt to follow a text book is to be deplored.

The study of the properties of matter, for instance, would be a fearful

and wonderful thing to set a class of little ones at as a beginning in

scientific work. Just what matter, and force, and molecules, and atoms

are may be well enough for the student who is old enough to begin to use

a book, but they would be but dry husks to a younger child. Many of the

careful classifications and analyses of topics in text books had far

better be used as summaries than in any other way; and a definition is

better when the pupil knows it is true than when he is about to find out

whether it is or not.

An ideal course in science would be one in which nothing should be

learned but that found out by the observation of the pupil himself under

the guidance of the teacher, necessary terms being given, but only when

the thing to be named had been considered, and the mind demanded the

term because of a felt need. Practically such a method is impossible in

its fullest sense, but a closer approach to it will be an advantage.

Among the numerous good results which will follow the study of physical

science are the following:

1. The cultivation of all the faculties of the child in a natural order,

thus making him grow into a ready, quick, and observing man. Education

in schools is too often shaped so as to repress instead of cultivate the

instinctive desire for the _knowledge of things_ which is found in every

child.

2. The mechanical skill which comes from the preparation and use of

apparatus.

3. The ability to follow directions.

4. The belief in stated scientific facts, the understanding of

descriptions, diagrams, etc.

5. The habitual scientific use of events which happen around us.

6. The study of the old to find the new. The principle of the telephone,

for instance, is as old as spoken language. The mere[1] pulses in the

air--carrying all the characteristics of what you say--may set in

vibration either the drum of my ear, or a disk of metal. How simple--and

how simple all true science is--when we understand it.

[Transcribers note 1: corrected from 'more']

8. The cultivation of the scientific judgment, and the inventive powers

of the mind. One great original investigator, made such by the direction

given his mind in one of our common schools, would be cheaply bought at

the price of all that the study of science in our schools will cost for

the next quarter of a century.

8. Honesty. If there is a study whose every tendency is more in the

direction of honesty and truthfulness--both with ourselves and with

others--than is the study of experimental science, I do not know what it

is.

Physical science, then, will help in making men and women out of our

boys and girls. It is worthy of a fair, earnest trial everywhere.

A few minutes each day in which a class or a school study science in

some of the ways I have indicated will give a knowledge at the end of a

term or a year of no mean value. The time thus spent will have rested

the pupils from their books, to which they will return refreshed, and

instead of being time lost from other study the work will have been made

enough more earnest and intense to make it again.

Apparatus for illustrating many of the ordinary facts of physics can be

devised from materials always at hand. Many more can be made by any

one skilled in the use of tools. In chemistry, the simplicity of the

apparatus, and comparative cheapness of ordinary chemicals, make the use

of a large number of beautiful and instructive experiments both easy and

cheap.

A nation is what its trades and manufactures--its inventions and

discoveries--make it; and these depend on its trained scientific men.

Boys become men. Their growing minds are waiting for what I urge you

to offer. Science has never advanced without carrying practical

civilization with it--but it has never truly advanced save by the use of

the experimental method. _And it never will_.

Let us then look forward to the time when our boys and young men--our

girls and young women--shall extend the boundaries of human knowledge by

its use, fitted so to do by what we may have done for them.

* * * * *

GEOGRAPHICAL SOCIETY OF THE PACIFIC.

This society is a recent organization, the objects of which are to

encourage geographical exploration and discovery; to investigate and

disseminate geographical information by discussion, lectures, and

publications; to establish in this, the chief maritime city of the

Western States, for the benefit of commerce, navigation, and the

industrial and material interests of the Pacific slope, a place where

the means will be afforded of obtaining accurate information not only of

the countries bordering on the Pacific ocean, but of every part of the

habitable globe; to accumulate a library of the best books on geography,

history, and statistics; to make a collection of the most recent maps

and charts--especially those which relate to the Pacific coast, the

islands of the Pacific and the Pacific ocean--and to enter into

correspondence with scientific and learned societies whose objects

include or sympathize with geography.

The society will publish a bulletin and an annual journal, which will

interchange with geographical and other societies. Monthly meetings are

to be held, at which original papers will be read or lectures be

given; and to which, as well as to the entertainments to distinguished

travelers, to the conversazioni, and to the informal evenings, the

fellows of the society will have the privilege of introducing their

friends. The initiation fee to the society is $10; monthly dues $1; life

fellowship $100.

At a meeting held at the Palace Hotel on the 12th May, the following

gentlemen were elected for the ensuing year: President, Geo. Davidson;

Vice-Presidents, Hon. Ogden Hoffman, Wm. Lane Booker, H.B.M. Consul, and

John R. Jarboe; Foreign Corresponding Sec., Francis Berton; Home Cor.

Sec., James P. Cox; Treas., Gen. C. I. Hutchinson; Sec'y, C. Mitchell

Grant, F.R.G.S. The council is composed of the following: Hon. Joseph W.

Winans, Hon. J.F. Sullivan, Ralph C. Harrison, A.S. Hallidie, Thos. E.

Stevin, F.A.G.S., W.W. Crane, Jr., W.J. Shaw, C.P. Murphy, Thos. Brice,

Edward L.G. Steele, Gerrit L. Lansing, Joseph D. Redding. The Trustees

are Geo. Davidson, Wm. Lane Booker, Hon. Jno. S. Hager, Geo. Chismore,

M.D., Selim Franklin.

* * * * *

THE BEHRING'S STRAITS CURRENTS.

It will be remembered that a short time since we mentioned the fact that

W.H. Dall, of the U. S. Coast Survey, who has passed a number of years

in Alaskan waters, on Coast Survey duty, denied the existence of any

branch of the Kuro Shiwo, or Japanese warm stream, in Behring's Straits.

That is, he failed to find evidence of the existence of any such

current, although he had made careful observations. At the islands in

Behring's Straits, his vessel had sailed in opposite directions with ebb

and flood tide, and he thought the only currents there were tidal in

their nature. The existence or non-existence of this current is an

important point in Arctic research on this side of the continent.

At the last meeting of the Academy of Sciences, Prof. Davidson, of the

U. S. Coast Survey, author of the "Alaska Coast Pilot," refuted Dr.

Dall's opinion of the non-existence of a branch of the Kuro Shiwo, or

Japanese warm stream, from the north Pacific into the Arctic Ocean,

through Behring's Straits. He said that in 1857 he gave to the Academy

his own observations, and recently he had conferred with Capt. C.L.

Hooper, who commanded the U. S. steamer Thomas Corwin, employed as a

revenue steam cruiser in the Arctic and around the coast of Alaska.

Capt. Hooper confirms the opinions of all previous navigators, every one

of which, except Dr. Dall, say that a branch of this warm stream passed

northward into the Arctic through Behring's Strait. It is partly

deflected by St. Lawrence Island, and closely follows the coast on the

Alaskan side, while a cold current comes out south, past East Cape

in Siberia, skirting the Asiatic shore past Kamschatka, and thence

continues down the coast of China. He said ice often extended several

miles seaward, from East Cape on the Asiatic side of Behring Strait,

making what seamen call a false cape, and indicating cold water, while

no such formation makes off on the American side, where the water is

12 degrees warmer than on the Asiatic shore off the Diomede islands,

situated in the middle of Behring's Strait, the current varies in

intensity according to the wind.

Frequently it is almost nothing for several days, when after a series of

southerly winds the shallow Arctic basin has been filled, under a heavy

pressure, with an unusual volume of water, and a sudden change to

northerly winds, makes even a small current setting southward for a few

days, just as at times the surface currents set out our Golden Gate

continuously for 24 and 48 hours, as shown by the United States Coast

Survey tide gauges. Whalers report that the incoming water then flows

in, under the temporary outflowing stream.

Old trees, of a variety known to grow in tropical Japan, are floated

into the Arctic basin as far as past Point Barrow, on the American side,

but none are found on the Asiatic side, or near Wrangell Land, where a

cold stream exists, and ice remains late in the season. On the northern

side of the Aleutian islands are found cocoanut husks and other tropical

productions stranded along the beaches. The American coast of Alaska

has a much warmer climate than the Asiatic coast of Siberia, and the

American timber line extends very far north. The ice opens early in the

season on the American side, and invariably late on the Asiatic.

Capt. C. L. Hooper says that when just north of Behring's Strait, off

the American coast, in the Arctic basin, the U.S. steamer Thomas Corwin,

when becalmed for 24 hours, drifted 40 miles to the northward. From

all these, and other facts, and the unanimous testimony of American

whalemen, who have for years spent many months annually in the Arctic,

and from his own observations, he argued that a branch of the Kuro-Shiwo

or Japanese warm stream, unquestionably runs northward through Behring's

Strait into the Arctic basin along the northwestern coast of Alaska.

Prof. Davidson then called to mind the testimony in regard to the

existence of Plover Island, between Herald Island and Wrangell Land,

which he said was first made public through this academy. The evidence

of Capts. Williams and Thomas Long were recited and highly praised. One

of the officers of Admiral Rodgers' expedition climbed to near the top

of Herald Island, at a time of great refraction, when probably a false

horizon existed, and hence did not see Plover Island, although Wrangell

Land was in sight.

Prof. Davidson thinks all the authorities are against Dr. Dall, who

attributes the warm current he observed on the American coast to water

from the Yukon River and to the large expanse of shallow water exposed

to the sun's rays. As Dall's observations only covered a few days of

possibly exceptional weather, and the whalers and Captain Hooper's cover

vastly longer periods, and whalers all say it is a pretty hard thing to

beat southward through Behring's Strait, owing to the northerly current

setting into the Arctic, we are forced to the conclusion that Dr.

Dall has mistaken the exception for the rule, and his conclusions are

therefore erroneous. When, in 1824, Wrangell went north, he, like

others, always found broken ice and considerable open water. In 1867,

when Capt. Thomas Long made his memorable survey of the coast of

Wrangell Land, the season was an exceptionally open one, and in

California we had heavy rains, extending into July.

* * * * *

EXPERIMENTAL GEOLOGY.

ARTIFICIAL PRODUCTION OF CALCAREOUS PISOLITES AND OOLITES.

Mr. Stanislas Meunier communicates to _Le Nature_ an account of some

interesting specimens of globular calcareous matter, resembling

pisolites or peastones both in appearance and structure, which were

accidentally formed as follows: The Northern Railway Company, France,

desiring to purify some calciferous water designed for use in steam

boilers, hit upon the ingenious expedient of treating it with lime water

whose concentration was calculated exactly from the amount of lime

held in the liquid to be purified. The liquids were mixed in a vast

reservoir, to which they were led by parallel pipes, and by which they

were given a rapid eddying motion. The transformation of the

bicarbonate into neutral carbonate of lime being thus effected with

the accompaniment of a circling motion, the insoluble salt which

precipitated, instead of being deposited in an amorphous state, hardened

into globules, the sizes of which were strictly regulated by the

velocity of the currents. Those that have been formed at one and the

same operation are uniform, but those formed at different times vary

greatly--their diameters varying by at least one millimeter to one and

a half centimeters. The surface of the smaller globules is smooth, but

that of the larger ones is rough. Even by the naked eye, it may be

seen that both the large and small globules are formed of regularly

superposed concentric layers. If an extremely thin section be made

through one of them it is found that the number of layers is very great

and that they are remarkably regular (A). By the microscope, it has been

ascertained that each layer is about 0.007 of a millimeter in thickness.

On observing it under polarized light the calcareous substance is

discovered to be everywhere crystallized, and this suggests the question

whether the carbonate has here taken the form of aragonite or of

calcite. Examination has shown it to be the latter. The density of the

globules (2.58) is similar to that of ordinary varieties of calcite. It

is probable that if the operation were to take place under the influence

of heat, under the conditions above mentioned, aragonite would be

formed. It is hardly necessary to dwell upon the possible geological

applications of this mode of forming calcareous oolites and pisolites.

ON CRYSTALS OF ANHYDROUS LIME.

Some time ago it was discovered that some limestone, which had been

submitted for eighteen months to a heat of nearly 1,000 degrees in

the smelting furnaces of Leroy-Descloges (France), had given rise to

perfectly crystallized anhydrous lime. Figure C shows three of these

crystals magnified 300 diameters. It will be noticed that they have a

striking analogy with grains of common salt. They are, in fact, cubes

(often imperfect), but do not polarize light, as a substance of the

first crystalline system should. However, it is rarely the case that the

crystals do not have _some_ action on light. Most usually, when the two

Nicol prisms are crossed so as to cause extinction, the crystals present

the appearance shown at D. That is to say, while the central portion

is totally inactive there are seen on the margins zones which greatly

brighten the light.

[Illustration]

A and B.--Calcareous Pisolites and Oolites produced artificially.

A.--External aspect and section of a Pisolite. B.--Details of internal

structure as seen by the microscope.

C and D.--Crystals of anhydrous Lime obtained artificially. C.--Crystals

seen under the microscope in the natural light. D.--Crystals seen under

the microscope in polarized light.

The phenomenon is explained by the slow carbonization of the anhydrous

lime under the influence of the air; the external layers passing to the

state of carbonate of lime or Iceland spar, which, as well known, has

great influence on polarized light. This transformation, which takes

place without disturbing the crystalline state, does not lead to any

general modification of the form of the crystals, and the final product

of carbonization is a cubic form known in mineralogical language as

_epigene_. As the molecule of spar is entirely different in form

from the molecule of lime, the form of the crystal is not absolutely

preserved, and there are observed on the edges of the epigene crystal

certain grooves which correspond with a loss of substance. These grooves

are quite visible, for example, on the crystal to the left in Fig. D.

Up to the present time anhydrous lime has been known only in an

amorphous state. The experiment which has produced it in the form noted

above would doubtless give rise to crystallized states of other earthy

oxides likewise, and even of alkalino-earthy oxides.

COCCIDAE.

[Footnote: A paper recently read before the California Academy of

Sciences.]

By DR. H. BEHR.

With the exception of Hymenoptera there is no group of insects that

interfere in so many ways in good and evil with our own interests, as

that group of Homoptera called Coccidae.

But while the Hymenoptera command our respect by an intellect that

approaches the human, the Coccus tribe possesses only the lowest kind of

instinct, and its females even pass the greater part of their lives in

a mere vegetation state, without the power of locomotion or perception,

like a plant, exhibiting only organs of assimilation and reproduction.

But strange to say, these two groups, otherwise so very dissimilar,

exhibit again a resemblance in their product. Both produce honey and

wax.

It is true, the honey of this tribe is almost exclusively used by the

ants. But I have tasted the honey-like secretion of an Australian

lecanium living; on the leaves of Eucalyptus dumosus; and the manna

mentioned in Scripture is considered the secretion of Coccus manniparus

(Ehrenberg) that feeds on a tamarix, and whose product is still used by

the native tribes round Mount Sinai.

Several species of Coccides are used for the production of wax; many

more, among which the Cochenill, for dyes.

All these substances can be obtained in other ways, even the Cochenill

is to a great extent superseded by aniline dyes, but in regard to one

production, indispensable to a great extent, we are entirely dependent

on some insects of this family; it is the Shellac, lately also found in

the desert regions around the Gila and Colorado on the Larrea Mexicana.

You will remember that excellent treatise on this variety of Shellac,

written by Professor J.M. Stillman at Berkeley, on its chemical

peculiarities.

But all these different forms of utility fall very lightly in weight,

and can not even be counted as an extenuating circumstance, when we

compare them to the enormous evils brought on farmer and gardener by the

hosts of those Coccides that visit plantations, hothouses, and orchards.

To combat successfully against these insect-pests we have first to study

their habits and then adapt to them our remedies, which you will see

are more effective when well administered than those which we possess

against insect pests of other classes.

I give here only the outlines of their natural history, peculiarities

that are common to all, for it would be impossible to go into detail.

Where there are exceptions of practical importance I will mention them.

In countries with a well defined winter the winged males appear as

soon as white frosts are no more usual, and copulate with the unwieldy

limbless female, that looks more like a gall or morbid excrescence, than

a living animal. Shortly after the young ones are perceptible near the

withered body of their mother, covered by waxy secretions that look

somewhat like a feathery down.

These young ones are lively enough, they move about with agility, and

it is not till high summer that they fasten themselves permanently, and

lose feet and antennae, organs of locomotion and perception that are no

more of any use to them. (There is a slight difference in this regard

between different genera, as for instance, Coccus and Dorthesia retain

these organs in different degrees of imperfection, Lecanium and

Aspidiotus losing every trace of them.)

In this limbless, senseless state the females remain fall and winter.

Toward the end of winter these animated galls begin to swell, and those

containing males enter the state of the chrysalis, from which the males

emerge at the beginning of the warm season and fecundate the gall-like

females, which undergo neither chrysalis state nor any other change, but

die, or we may call it dissolve into their offspring, for there scarcely

remains anything of them, except a pruinous kind of down, after having

given birth to the young ones.

Now we come to the practical deduction from these facts. It is clear

that the only time when the scalebug can emigrate and infest a new

tree is the time when it is a larva, that is, when it has the power of

locomotion. In countries with a pronounced winter this time begins

much later than with us, but it ends about the same time, that is, the

beginning of August. I have seen the male of Aspidiotus in February, so

that the active larva may be expected in March, and the active Lecanium

Hesperidum I have seen last year, June 27, at Colonel Hooper's ranch in

Sonoma County. We may safely fix the time of the active scalebug from

March to August.

Notwithstanding the agility of the young scalebug, the voyage from one

tree to another, considering the minute size of the traveler, is an

undertaking but seldom succeeding, but one female bug, if we take

into account its enormous fertility, is sufficient to cover with its

grandchildren next year a tree of moderate size.

Besides there is another and much more effective way of transmigration

by the kind assistance of the ant who colonizes the scalebug as well for

its wax as it colonizes the Aphis for its honey. Birds on their feathers

and the gardener himself on his dress contribute to spread them.

But even the ant can not transplant the scalebug when it is once firmly

fixed by its rostrum.

It is evident, therefore, that the time for the application of

insecticides is the time when all the scalebugs are fixed, that is about

the end of July or beginning of August. All previous application will

clean the tree or plant only for a time, and does not prevent a more or

less numerous immigration from the neighboring vegetation, especially if

an ant-hill is not far off.

As to the insecticide, there are to be applied two very effective ones,

each with its advantages and disadvantages.

1. Petroleum and its different preparations.

2. Lye or soap.

The petroleum is the best disinfectant. It can safely be applied to any

cutting or stem, as long as it is not planted, but is one of the most

invidious substances when applied to vegetation in the garden, or

fields. If effectively applied, it can not be prevented from running

down the bark of the tree and entering the ground, where every drop

binds a certain amount of earth to an insoluble substance, in which

state it remains for ever. With every application the quantity of these

insoluble compounds is augmented and sterility added.

If I am not mistaken, it was near Antwerp--at least I am certain it was

in Belgium--where the first experience of this kind is recorded.

In France, preparations of coal tar have been recommended and have

been lately used in the form of a paint. May be that in this form the

substance is not so apt to enter into combinations with the soil. At any

rate, the method is of too recent a date to permit any conclusions about

the final result of these applications, as the invidious nature of the

substance produces, by gradual accumulation, its effects, which are not

perceived until they are irreparable.

2. Lye or soap. The application of these insecticides requires more

care, and is therefore more troublesome. But instead of attracting

fertility from the soil, they add to it. In Southern Europe soap

and water has been for many years the remedy against the Lecanium

Hesperidum. The method applied by the farmers in Portugal, as described

to me by Dr. Bleasdale, is perhaps the most perfect one. The Portuguese

have very well observed that the colonization of scalebugs always begins

at the lowest end of the trunk and pretend, therefore, that the scalebug

comes out of the ground. This, of course, is not the case, but may their

interpretation be an error, they have been practical enough in utilizing

their observation about the invasion beginning near the roots. They

knead a ring of clay round the tree, in which ring the soap water runs

when they wash the tree, and besides, they fill frequently the little

ditch formed by this ring.

This arrangement of course is only possible in climates of a rainy

summer.

As it is our object to make our knowledge as available as possible for

practical purposes, I repeat for the benefit of cultivators the advice,

without repeating the reasoning:

1. Use the petroleum for disinfecting imported trees and cuttings:

2. Use soap for cleaning trees planted in your orchard.

3. If you must use the petroleum in your garden, use it in August, when

a single application is sufficient.

* * * * *

AGRICULTURAL ITEMS.

The exportation of dried apples from this country to France has greatly

increased of late years, and now it is said that a large part of this

useful product comes back in the shape of Normandy cider and light

claret.

A.B. Goodsell says in the _New York Tribune_: "Put your hen feed around

the currants. I did this twice a week during May and June, and not a

currant worm was seen, while every leaf was eaten off other bushes 150

feet distant, and not so treated."

Buckwheat may be made profitable upon a piece of rough or newly cleared

ground: No other crop is so effective in mellowing rough, cloddy land.

The seed in northern localities should be sown before July 12; otherwise

early frosts may catch the crops. Grass and clover may sometimes be sown

successfully with buckwheat.

The London News says: "Of all poultry breeding, the rearing of the goose

in favorable situations is said to be the least troublesome and most

profitable. It is not surprising, therefore, that the trade has of late

years been enormously developed. Geese will live, and, to a certain

extent, thrive on the coarsest of grasses."

When a cow has a depraved appetite, and chews coarse, indigestible

things, or licks the ground, it indicates indigestion, and she should

have some physic. Give one pint and a half of linseed oil, one pound of

Epsom salts, and afterward give in some bran one ounce of salt and the

same of ground ginger twice a week.

Asiatic breeds of fowl lay eggs from deep chocolate through every shade

of coffee color, while the Spanish, Hamburg, and Italian breeds are

known for the pure white of the eggshell. A cross, however remote, with

Asiatics, will cause even the last-named breeds to lay an egg slightly

tinted.

In setting out currant bushes care should be exercised not to place any

buds under ground, or they will push out as so many suckers. Currants

are great feeders, and should be highly manured. To destroy the worm,

steep one table-spoonful of hellebore in a pint of water, and sprinkle

the bushes. Two or three sprinklings are sufficient for one season.

Mr. Joseph Harris, of Rochester, makes a handy box for protecting melons

and cucumbers from insect enemies. Take two strips of board of the

required size, and fasten them together with a piece of muslin, so the

muslin will form the top and two sides of the box. Then stretch into

box form by inserting a small strip of wood as a brace between the two

boards. This makes a good, serviceable box, and, when done with for the

season, it can be packed into a very small space, by simply removing the

brace and bringing the two board sides together. As there is no patent

on the contrivance, anybody can make the boxes for himself.

Mr. C. S. Read recently said before the London Fanners' Club: "American

agriculturists get up earlier, are better educated, breed their stock

more scientifically, use more machinery, and generally bring more

brains to bear upon their work than the English farmer. The practical

conclusion is, that if farmers in England worked hard, lived frugally,

were clad as meanly as those of the States, were content to drink filthy

tea three times a day, read more and hunted less, the majority of them

may continue to live in the old country."--_N. E. Farmer_.

* * * * *

TIMBER TREES.

A paper was read by Sir R. Christison at the last meeting of the

Edinburgh Botanical Society upon the "Growth of Wood in 1880." In a

former paper, he said, he endeavored to show that, in the unfavorable

season of 1879, the growth of wood of all kinds of trees was materially

less than in the comparatively favorable season of 1878. He had now to

state results of measurements of the same trees for the recent favorable

season of 1880. The previous autumn was unfavorable for the ripening of

young wood, and the trees in an unprepared condition were exposed during

a great part of December, 1879, to an asperity of climate unprecedented

in this latitude. This might have led one to expect a falling off in the

growth of wood, and it appeared, from comparison of measurements, that,

with very few exceptions, the growth of wood last year was even more

below the average of favorable years than that of the bad year, 1879.

Thus, in fifteen leaf-shedding trees of various species, exclusive of

the oak, the average growth of trunk girth in three successive years

was: 1878, 8-10ths; 1879, 45-100ths; 1880, 3-10ths and a half. In

four specimens of the oak tribe, the growth was: 1878, 8-10ths; 1879,

77-100ths; 1880, 54-100ths. In twenty specimens of the evergreen

Pinaceae the growth was: 1878, 8-10ths; 1879, 7-10ths; 1880, 6-10ths and

a half. After giving details in regard to particular trees, Sir Robert

stated, as general deductions from his observations, that leaf-shedding

trees, exclusive of the oak, suffered most; that the evergreen Pinaceae

suffered least; and that there was some power of resistance on the part

of the oak tribe which was remarkable, the power of resistance of the

Hungary oak being particularly deserving of attention. In another

communication on the "extent of the season of growth," Sir Robert

stated, as the result of observations on five leaf-shedding and five

evergreen trees, that in the case of the former, even in a fine year,

the growth of wood was confined very nearly, if not entirely, to the

months of June, July, and August; while in the case of the latter growth

commenced a month sooner, terminating, however, about the same time. Mr.

A. Buchan said it was proposed that the inquiry should be taken up more

extensively over Scotland.

* * * * *

MEDICAL USES OF FIGS.--Prof. Bouchut speaks (_Comptes Rendus_) of some

experiments he has made, going to show that the milky juice of the

fig-tree possesses a digestive power. He also observed that, when some

of this preparation was mixed with animal tissue, it preserved it

it from decay for a long time. This fact, in connection with Prof.

Billroth's case of cancer of the breast, which was so excessively foul

smelling that all his deodorizers failed, but which, on applying a

poultice made of dried figs cooked in milk, the previously unbearable

odor was entirely done away with, gives an importance to this homely

remedy not to be denied.--_Medical Press and Circ._

* * * * *

BLOOD RAIN.

The sensibilities of ignorant or superstitious people have at various

times been alarmed by the different phenomena of so-called blood, ink,

or sulphur rains. Ehrenberg very patiently collected records of the most

prominent instances of these, and published them in his treatise on the

dust of trade winds. Some, it is known, are due to soot; others, to

pollen of conifers or willows; others, to the production of fungi and

algae.

Many of the tales of the descent of showers of blood from the clouds

which are so common in old chronicles, depends, says Mr. Berkeley, the

mycologist, upon the multitudinous production of infusorial insects or

some of the lower algae. To this category belongs the phenomenon known

under the name of "red snow." One of the most peculiar and remarkable

form, which is apparently virulent only in very hot seasons, is caused

by the rapid production of little blood-red spots on cooked vegetables

or decaying fungi, so that provisions which were dressed only the

previous day are covered with a bright scarlet coat, which sometimes

penetrates deeply into their substance. This depends upon the growth of

a little plant which has been referred to the algae, under the name

of _Palmellae prodigiosa_. The rapidity with which this little plant

spreads over meat and vegetables is quite astonishing, making them

appear precisely as if spotted with arterial blood; and what increases

the illusion is, that there are little detached specks, exactly as if

they had been squirted from a small artery. The particles of which the

substance is composed have an active molecular motion, but the morphosis

of the production has not yet been properly observed. The color of the

so-called "blood rain" is so beautiful that attempts have been made

to use it as a dye, and with some success; and could the plant be

reproduced with any constancy, there seems little doubt that the color

would stand. On the same paste with the "blood-rain" there have been

observed white, blue, and yellow spots, which were not distinguishable

in structure and character.

* * * * *

TOPICAL MEDICATION IN PHTHISIS.

Dr. G.H. Mackenzie reports in the _Lancet_ an acute case of phthisis

which was successfully treated by him by causing the patient to respire

as continuously as possible, through a respirator devised for the

purpose, an antiseptic atmosphere. The result obtained appears to bear

out the experiments of Schueller of Greifswald, who found that animals

rendered artificially tuberculous were cured by being made to inhale

creosote water for lengthened periods. Intermittent spraying or inhaling

does not produce the same result. In order to insure success the

application to the lungs must be made _continuously_. For this purpose

Dr. Mackenzie has used various volatile antiseptics, such as creosote,

carbolic acid, and thymol. The latter, however, he has discarded

as being too irritating and inefficient. Carbolic acid seems to be

absorbed, for it has been detected freely in the urine after it had been

inhaled; but this does not happen with creosote. As absorption of the

particular drug employed is not necessary, and therefore not to be

desired, Dr. Mackenzie now uses creosote only, either pure or dissolved

in one to three parts of rectified spirits. "Whether," says he, "the

success so far attained is due to the antidotal action of creosote and

carbolic acid on a specific tubercular neoplasm, or to their action as

preventives of septic poisoning from the local center in the lungs,

it is certain that their continuous, steady use in the manner just

described has a decidedly curative action in acute phthisis, and is

therefore, worthy of an extended trial."

* * * * *

ON THE LAW OF AVOGADRO AND AMPERE.

The Scientific American Supplement of May 14,1881, contains, under this

head, Mr. Wm. H. Greene's objections to my demonstration (in No. 270

of the same paper) of the error of Avogadro's hypothesis. The most

important part of my argument is based on the evidence afforded by the

compound cyanogen; and Mr. Greene, directing his attention to this

subject in the first place, states that because cyanogen combines

with hydrogen or with chlorine, without diminution of volumes, I have

concluded that the hypothesis falls to the ground. This statement has

impressed me with the conviction that Mr. Greene has failed to perceive

the difficulty which is at the bottom of the question, and I will,

therefore, present the subject more fully and comprehensively.

The molecule of any elementary body is, on the ground of the hypothesis,

assumed to be a compound of two atoms, and the molecule of carbon

consequently C_2=24; that of nitrogen N_2=28. Combination of the two,

according to the same hypothesis, takes place by substitution; the

atoms are supposed to be set free and to exchange places, forming a

new compound different from the original only in this: that each new

particle contains an atom of each of the two different substances, while

each original particle consists of two identical atoms. The product is,

therefore, assumed to be, and can, under the circumstances, be no other

than particles of the composition CN and weight 26. These particles are

molecules, according to the definition laid down, just as C_2 and N_2;

but there is this essential difference, that the specific gravity of

cyanogen gas, 26, coincides with the molecular weight, while the assumed

molecular weight, N_2=28, is twice as great as the specific gravity of

the gas, N=14.

In using the term molecular weight, it is to be remembered that it does

not express the weight of single molecules, but only their relative

weight, millions of millions molecules being contained in the unit of

volume. But on the hypothesis that there is the same number of molecules

in the same volume of any gas, the specific gravities of gases can be,

and are, identified with their molecular weights, and, on the ground of

the hypothesis again, the unit of the numbers which enter into every

chemical reaction and constitute the molecular weight, is stipulated to

be that contained in two volumes.

The impossibility of the correctness of the hypothesis is now revealed

by the fact just demonstrated, that in the case of nitrogen the specific

gravity does not coincide with the molecular weight. If equal volumes

contain the same number of molecules, the specific gravities and the

molecular weights must be the same; and if the specific gravities and

molecular weights are not the same, equal volumes cannot contain the

same number of molecules. The assumed molecular weight of nitrogen is

twice as great as the specific gravity, but the molecular weight and

the specific gravity of cyanogen are identical; the number of molecules

contained in one volume of cyanogen must, therefore, necessarily be

twice as great as the number contained in one of nitrogen, and this is

fully and completely borne out by the chemical facts.

In saying that when cyanogen combines with chlorine there is naturally

no condensation, Mr. Greene has no idea that this natural law is fatal

to his artificial law of Avogadro and Ampere; "for," continues he, "the

theory is fulfilled by the actual reaction." It is not. The theory

requires two vols. of cyanogen and two vols. of chlorine, that is, the

unit of numbers, to enter into reaction and to produce two vols. of

the compound. But they produce four vols., and the non-condensation is

therefore in opposition to the theory. It is true beyond doubt that the

molecular weight of cyanogen chloride is contained in two volumes, in

spite of the hypothesis, not on the ground of it; two vols. + two vols.,

producing four vols.; two vols. could, theoretically, contain only half

the unit of numbers, and there seems to be no escape from the following

general conclusions:

1. Two vols. of CNCl, representing the unit of numbers, the constituent

weights, C=12, N=14, Cl=35.5, must each, likewise, represent the same

number; the molecular weight is, therefore, contained in one vol. of N

or Cl, but in two of CNCl and equal numbers are not contained in equal

volumes.

2. The weights N=14, Cl=35.5 occupy in the free state one volume, but

in the combination, CNCl, two volumes; their specific gravity is,

therefore, by chemical action reduced to one half. The fact thus

elicited of the variability and variation of the specific gravity is of

fundamental importance and involves the irrelevancy of the mathematical

demonstration of the hypothesis. In this demonstration the specific

gravity is assumed to be constant, and this assumption not holding good,

and the number of molecules in unit of volume being reduced to one half

when the specific gravity is reduced to the same extent by chemical

action, it is obvious that the mathematical proof must fail. Mr. Greene

states that I have proceeded to demolish C. Clerk Maxwell's conclusion

from mathematical reasoning. This is incorrect; I have found no fault

with the conclusion of the celebrated mathematician, and consider his

reasoning unimpeachable. I am also of opinion that he is entitled to

great credit and respect for the prominent part he has taken in the

development of the kinetic theory, and further think that it was for

the chemists to produce the fact of the variability of the specific

gravities, which they would probably not have failed to do but for the

prevalence of Avogadro's hypothesis, which is virtually the assertion of

the constancy of the specific gravities.

3. The unit of numbers being represented by Cl=35.5, it is likewise

represented by H=1, and as the product of the union of the two elements

is HCl, 36.5 = two vols., combination takes place by addition and not by

substitution; consequently are

4. The elementary molecules not compounds of atoms? And the distinction

between atoms and molecules is an artificial one, not justified by the

natural facts.

5. Is the molecular weight not in every instance = two volumes?

These conclusions overthrow all the fundamental assumptions on which the

hypothesis rests, and leave it, in the full meaning of the term, without

support. Though Mr. Greene states that my arguments are based upon

entirely erroneous premises, he has not even attempted to invalidate a

single one of my premises.

As he considers the non-condensation to be natural in the case of

cyanogen and chlorine, the condensation of two vols. of HCl + two vols.

of H_3N to two vols. of NH_4Cl ought to appear to him unnatural. He,

however, contends for it, and tries, on this solitary occasion, to

strengthen his opinion by authority, though the proof, if it could be

given, that ammonium chloride at the temperature of volatilization is

decomposed into its two constituents, would be insufficient to uphold

the theory.

The ground on which Mr. Greene assumes a partial decomposition at 350 deg.

C. is the slight excess of the observed density (14.43) over that

corresponding to four vols. (13.375). There is, however, a similar

slight excess in the case of the vapor of ammonium cyanide, the same

values being respectively 11.4 and 11; and as this compound is volatile

at 100 deg. C and, at the same time, is capable to exist at a very high

temperature, being formed by the union of carbon with ammonia, nobody

has ever, as far as I am aware, maintained that it is completely or

partially decomposed at volatilization. The excess of weight not being

due, therefore, to such cause in this case, it cannot be due to it in

the other.

The question being whether the molecular weight of ammonium chloride

is two vols. or four vols., an idea of the magnitude of the assumed

decomposition is conveyed by the proportion of the volume of the

decomposed salt to the volume of the non-decomposed, and Mr. Greene's

quotation of the percentage of weight is irrelevant and misleading, and

his number not even correct. A mixture containing

1.055 vols. of spec. gr. 26.75 = 28.22 and

12.32 " " " " 13.375 = 164.78

------ ------

13.375 " 193

has the spec. gr. 193 / 13.375 = 14.43. The proportion in one vol. of

the undecomposed to the decomposed salt is, therefore, as 1 to 11.68 and

the percentage of volume of the former 0.0789, and that of weight 28.22

/ 193 = 0.146, and not 0.16.

It is not easy to imagine why a small fraction of the heavy molecules

should be volatilized undecomposed, the temperature being sufficient

to decompose the great bulk. Marignac assumes, indeed, partial

decomposition, but the difficulties which he encountered in making the

experiments, on the results of which his opinion rests, were so great

that he himself accords to the numbers obtained by him only the value of

a rough approximation.

The heat absorbed in volatilization will comprise the heat of

combination as well as of aggregation, if decomposition takes place, and

will therefore be the same as that set free at combination. Favre and

Silbermann found this to be 743.5 at ordinary temperature, from which

Marignac concludes that it would be 715 for the temperature 350 deg.; he

found as the heat of volatilization 706, but considers the probable

exact value to be between 617 and 818.[1]

[Footnote 1: See _Comptes Rendus_, t. lxvii., p. 877.]

An uncertainty within so wide a range does not justify the confidence

of Mr. Greene which he expresses in these words: "It is, therefore,

extremely probable that ammonium chloride is almost entirely

dissociated, even at the temperature of volatilization." By Boettinger's

apparatus a decomposition may possibly have been demonstrated, but it

remains to be seen whether it is not due to some special cause.

When Mr. Greene says that the relations between the physical properties

of solids and liquids and their molecular composition can in no

manner affect the laws of gases, nobody is likely to dissent; but the

conclusion that their discussion is foreign to the question of the

number of molecules in unit of volume does by no means follow. If the

specific gravity of a solid or the weight of unit of volume represents

a certain number of molecules, and is found to occupy two volumes in a

compound of the solid with another solid, the number of molecules in one

volume is reduced to one half. This I have shown to be the case in a

number of compounds, and the decrease of the specific gravity with

increase of the complexity of composition appears to be a general law,

as may be concluded from the very low specific gravity of the most

highly organized compounds, for instance the fatty bodies, the molecules

of which, being composed of very many constituents, are of heavy weight;

and likewise the compounds which occur in combination with water and

without it, the simpler compound having invariably a greater specific

gravity than the one combined with water; for instance:

BaH_2O_2 sp. gr. 4.495

" " + 8H_2O " 1.656

S_2H_2O_2 " 3.625

" " + 8H_2O " 1.396

FeSO_4 " 3.138

" + 7H_2O " 1.857

and so in every other case. This is now a recurrence of what takes

place in gases, and proves the fallacy of the hypothesis; for if these

compounds could be volatilized the vapor densities would necessarily

vary in the inverse proportion of the degree of composition.

The reproach that Berthelot has been endeavoring for nearly a quarter of

a century to hold back the progress of scientific chemistry, is a great

and unjustifiable misrepresentation of the distinguished chemist

and member of the Institute of France, who has done so much for

thermo-chemistry, and the more unfortunate as it seems to serve only the

purpose of a prelude to the following sentences: "But Mr. Vogel cannot

claim, as can Mr. Berthelot, any real work or experiment, however

roughly performed, suggested by the desire to prove the truth of his

own views. Let him not, then, bring forth old and long since explained

discrepancies, ... but when he will have discovered new or overlooked

facts ... chemists will gladly listen." ... Mr. Greene is here no longer

occupied to investigate whether what I have said concerning Avogadro's

hypothesis is true or false, but with myself he has become personal, and

in noticing his remarks my sole object is to contend against an error

which is much prevalent. If, according to Mr. Greene, the real work of

science consists in experimenting, and conclusions unsupported by our

own experiments have no value, it does not appear for what purpose he

has published his answer to my paper; an experiment of his, settling

Marignac's uncertain results, would have justified the reliance he

places on them. The ground he takes is utterly untenable. Experiments

are necessary to establish facts; without them there could be no

science, and the highest credit is due to those who perform successfully

difficult or costly experiments. Experimenting is, however, not the

aim and object of science, but the means to arrive at the truth; and

discoveries derived from accumulated and generally accepted facts are

not the less valuable on account of not having been derived from new and

special experiment.

It is, further, far from true that the real work of science consists

in experimenting; mental work is not less required, and the greatest

results have not been obtained by experimenters, but by the mental labor

of those who have, from the study of established facts, arrived at

conclusions which the experimenters had failed to draw. This is

naturally so, because a great generalization must explain all the facts

involved, and can be derived only from their study; but the attention

of the experimenter is necessarily absorbed by the special work he

undertakes. I refer to the three greatest events in science: the

discovery of the Copernican system, the three laws of Kepler, and

Newton's law of gravitation, none of which is due to direct and special

experimentation. Copernicus was an astronomer, but the discovery of his

system is due chiefly to his study of the complications of the Ptolemaic

system. Kepler is a memorable witness of what can be accomplished by

skillful and persistent mental labor. "His discoveries were secrets

extorted from nature by the most profound and laborious research." The

discovery of his third law is said to have occupied him seventeen years.

Newton's great discovery is likewise the result of mental labor; he was

enabled to accomplish it by means of the laws of Kepler, the laws of

falling bodies established by Galileo, and Picard's exact measurement of

a degree of a meridian.

If, then, mental work is as indispensable as experimental, it is not

less true that there are men more specially fitted for the one, others

for the other, and the best interests of science will be served when

experiments are made by those specially adapted, skillful, and favorably

situated, and the possibly greatest number of men, able and willing to

do mental work, engage in extracting from the accumulated treasures of

experimental science all the results which they are capable to yield.

Any truth discovered by this means is clear gain, and saves the waste

of time, labor, and money spent in unnecessary experiment. Mr. Greene's

zeal for experiment and depreciation of mental work would be in order,

if ways and means were to be found to render the advancement of science

as difficult and slow as possible; they are decidedly not in the

interest of science, and can not have been inspired by a desire for its

promotion.

As the evidence of the specific heats of the fallacy of Avogadro's

hypothesis involves lengthy explanations, the subject is reserved for

another paper.

San Francisco, Cal., May, 1881.

E. VOGEL.

* * * * *

DYEING REDS WITH ARTIFICIAL ALIZARIN.

By M. MAURICE PRUD'HOMME.

Since several years, the methods of madder dyeing have undergone a

complete revolution, the origin of which we will seek to point out. When

artificial alizarin, thanks to the beautiful researches of Graebe and

Liebermann, made its industrial appearance in 1869, it was soon found

that the commercial product, though yielding beautiful purples, was

incapable of producing brilliant reds (C. Koechlin). While admitting

that the new product was identical with the alizarin extracted from

madder, we were led to conclude that in order to produce fine Turkey

reds, the coloring matters which accompany alizarin must play an

important part. This was the idea propounded by Kuhlmann as far back as

1828 (_Soc. Ind. de Mulhouse_, 49, p. 86). According to the researches

of MM. Schuetzenberger and Schiffert, the coloring matters of madder

are alizarin, purpurin, pseudopurpurin, purpuroxanthin, and an orange

matter, which M. Rosenstiehl considers identical with hydrated purpurin.

Subsequently, there have been added to the list an orange body,

purpuroxantho-carbonic acid of Schunck and Roemer, identical with the

munjistin found by Stenhouse in the madder of India. It was known

that purpuroxanthin does not dye; that pseudopurpurin is very easily

transformed into purpurin, and the uncertainty which was felt concerning

hydrated purpurin left room merely for the hypothesis that Turkey-red

is obtained by the concurrent action of alizarin and purpurin. In the

meantime, the manufacture of artificial alizarin became extended, and a

compound was sold as "alizarin for reds." It is now known, thanks to the

researches of Perkin, Schunck, Roemer, Graebe, and Liebermann, that in

the manufacture of artificial alizarin there are produced three distinct

coloring matters--alizarin, iso or anthrapurpurin, and flavopurpurin,

the two latter being isomers of purpurin. We may remark that purpurin

has not been obtained by direct synthesis. M. de Lalande has produced

it by the oxidation of alizarin. Alizarin is derived from

monosulphanthraquinonic acid, on melting with the hydrate of potassa or

soda. It is a dioxyanthraquinone.

Anthrapurpurin and flavopurpurin are obtained from two isomeric

disulphanthraquinonic acids, improperly named isoanthraflavic and

anthraflavic acids, which are converted into anthrapurpurin and

flavopurpurin by a more profound action of potassa. These two bodies are

trioxyanthraquinones.

We call to mind that alizarin dyes reds of a violet tone, free from

yellow; roses with a blue cast and beautiful purples. Anthrapurpurin and

flavopurpurin differ little from each other, though the shades dyed

with the latter are more yellow. The reds produced with these coloring

matters have a very bright yellowish reflection, but the roses are too

yellow and the purples incline to a dull gray.

Experience with the madder colors shows that a mixture of alizarin and

purpurin yields the most beautiful roses in the steam style, but it is

not the same in dyeing, where the roses got with fleur de garance have

never been equaled.

"Alizarins for reds" all contain more or less of alizarin properly

so-called, from 1 to 10 per cent., along with anthrapurpurin and

flavopurpurin. This proportion does not affect the tone of the reds

obtained further than by preventing them by having too yellow a tone.

The first use of the alizarins for reds was for application of styles,

that is colors containing at once the mordant and the coloring matter

and fixed upon the cloth by the action of steam. Good steam-reds were

easily obtained by using receipts originally designed for extracts of

madder (mixtures of alizarin and purpurin). On the other hand, the first

attempts at dyeing red grounds and red pieces were not successful. The

custom of dyeing up to a brown with fleur and then lightening the shade

by a succession of soapings and cleanings had much to do with this

failure. Goods, mordanted with alumina and dyed with alizarin for reds

up to saturation, never reach the brown tone given by fleur or garancin.

This tone is due in great part to the presence of fawn colored matters,

which the cleanings and soapings served to destroy or remove. The same

operations have also another end--to transform the purpurin into its

hydrate, which is brighter and more solid. The shade, in a word, loses

in depth and gains in brightness. With alizarins for reds, the case is

quite different; they contain no impurities to remove and no bodies

which may gain brightness in consequence of chemical changes under the

influence of the clearings and soapings. These have only one result, in

addition to the formation of a lake of fatty acid, that is to make the

shades lose in intensity. The method of subjecting reds got up with

alizarin to the same treatment as madder-reds was faulty.

There appeared next a method of dyeing bases upon different

principles. The work of M. Schuetzenberger (1864) speaks of the use of

sulpho-conjugated fatty acids for the fixation of aniline colors. In

England, for a number of years, dyed-reds had been padded in soap-baths

and afterwards steamed to brighten the red. In 1867, Braun and Cordier,

of Rouen, exhibited Turkey reds dyed in five days. The pieces were

passed through aluminate of soda at 18 deg. B., then through ammonium

chloride, washed, dyed with garancin, taken through an oil-bath, dried

and steamed for an hour, and were finally cleared in the ordinary manner

for Turkey-reds. The oil-bath was prepared by treating olive-oil with

nitric acid. This preparation, invented by Hirn, was applied since 1846

by Braun (Braun and Cordier). Since 1849, Gros, Roman, and Marozeau,

of Wesserling, printed fine furniture styles by block upon pieces

previously taken through sulpholeic acid. When the pieces were steamed

and washed the reds and roses were superior to the old dyed reds and

roses produced at the cost of many sourings and soapings. Certain makers

of aniline colors sold mixtures ready prepared for printing which were

known to contain sulpholeic acids. There was thus an idea in the air

that sulpholeic acid, under the influence of steam, formed brilliant and

solid lakes with coloring matters. These facts detract in nothing from

the merit of M. Horace Koechlin, who combined these scattered data

into a true discovery. The original process may be summed up under the

following heads: Printing or padding with an aluminous mordant, which is

fixed and cleaned in the usual manner; dyeing in alizarin for reds with

addition of calcium acetate; padding in sulpholeic acid and drying;

steaming and soaping. The process was next introduced into England,

whence it returned with the following modifications; in place of

olive-oil or oleic acid, castor oil was used, as cheaper, and the number

of operations was reduced. Castor oil, modified by sulphuric acid, can

be introduced at once into the dye-beck, so that the fixation of the

coloring matter as the lake of a fatty acid is effected in a single

operation. The dyeing was then followed by steaming and soaping.

For red on white grounds and for red grounds, a mordant of red liquor at

5 deg. to 6 deg. B. is printed on, with a little salt of tin or nitro-muriate of

tin. It is fixed by oxidation at 30 deg. to 35 deg. C., and dunged with cow-dung

and chalk. The pieces are then dyed with 1 part alizarin for reds at 10

per cent., 1/4 to 1/2 oil for reds (containing 50 per cent.), 1-6th part

acetate of lime at 15 deg. B., giving an hour at 70 deg. and half an hour at the

same heat. Wash, pad in oil (50 to 100 grms. per liter of water), dry on

the drum, or better, in the hot flue, and steam for three-quarters to an

hour and a half. The padding in oil is needless, if sufficient oil has

been used in dyeing, and the pieces may be at once dried and steamed.

Wash and soap for three-quarters of an hour at 60 deg.. Give a second

soaping if necessary. If there is no fear of soiling the whites, dye at

a boil for the last half-hour, which is in part equal to steaming.

Red pieces and yarns may be dyed by the process just given for red

grounds; or, prepare in neutral red oil, in the proportion of 150 grms.

per liter of water for pieces and 15 kilos for 100 kilos of yarns. For

pieces, pad with an ordinary machine with rollers covered with

calico. Dry the pieces in the drum, and the yarn in the stove. Steam

three-quarters of an hour at 11/2 atmosphere. Mordant in pyrolignite of

alumina at 10 deg. B., and wash thoroughly. Dye for an hour at 70 deg., and half

an hour longer at the same heat, using for 100 kilos of cloth or yarn 20

kilos alizarin at 10 per cent., 10 kilos acetate of lime at 18 deg. B., and

5 kilos sulpholeic acid. Steam for an hour. Soap for a longer or shorter

time, with or without the addition of soda crystals. There may be added

to the aluminous mordant a little salt of tin to raise the tone. Lastly,

aluminate of soda may be used as a mordant in place of red liquor or

sulphate of alumina.

Certain firms employ a so-called continuous process. The pieces are

passed into a cistern 6 meters long and fitted with rollers. This

dye-bath contains, from 3 to 5 grms. of alizarin per liter of water, and

is heated to 98 deg.. The pieces take 5 minutes to traverse this cistern,

and, owing to the high temperature and the concentration of the dye

liquor, they come out perfectly dyed. Two pieces may even be passed

through at once, one above the other. As the dye-bath becomes exhausted,

it must be recruited from time to time with fresh quantities of

alizarin. The great advantage of this method is that it economizes not

merely time but coloring matter.

The quantity of acetate of lime to be employed in dyeing varies with the

composition of the mordant and with that of the water. Schlumberger has

shown that Turkey-red contains 4 molecules of alumina to 3 of lime.

Rosenstiehl has shown that alumina mordants are properly saturated if

two equivalents of lime are used for each equivalent of alizarin, if the

dyeing is done without oil. These figures require to be modified when

the oil is put into the dye beck, as it precipitates the lime. Acetate

of lime at 15 deg. B., obtained by saturating acetic acid with chalk and

adding a slight excess of acetic acid, contains about 1/4 mol. acetate of

lime.--_Bulletin de la Societe Chimique de Paris._

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