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CHEMICAL NEWS 232 Estimation of Potassium as Acid Tartrate.

Dec. 1, 1876. 100 d=114 x+1'9 (100 – *)

being tested by a titrated alkaline solution is the quality 100 d=11'4 *+190 – 1'9*

which, combined with its feeble solubility, recommended

it as the compound in which to obtain potassium for 100 d= 9.5 x+190

analysis. We must, however, increase its insolubility if whence

accurate results are to be obtained, and this can be easily 100 d - 190

accomplished by means of alcohol. 95

The insolubility of cream of tartar in a mixture of alMy purpose this evening is describe a process for the cohol and water is greater than in pure water. The estimation of potassium as acid tartrate,-a process which following table given by Chancel shows the solubility of has the advantage of being direct, and which gives results cream of tartar in water at several temperatures :much more rapidly than can be obtained by any other

100 c.c. of Water means, while for accuracy they compare favourably even

Degs. C. with those obtained by platinic chloride.

Cream of Tartar. The occasion which led me to estimate potassium as

0:24 acid tartrate was a series of experiments on the process

5

0*30 of Messrs. Duncan and Newlands for separating potassium

0:37 from the low products of sugar-houses by the addition of

15 sulphate of alumina, and the consequent production of

0:55 potassium alum. To avoid an excess of sulphate of

25

0.67 alumina, which would be a waste, it became necessary to

30

0:805 ascertain the quantity of potassium in each batch of pro

35

o'96 ducts. For this determination platinic chloride is not very

40

I'13 well adapted, as the first requisite was celerity rather than accuracy. The use of platinic chloride requires, in the Having had occasion to use this table repeatedly, I have first place, a thorough destruction of the organic matter verified these numbers and found them correct. by heat. The ashes, obtained as sulphates, are treated, Chancel has also given us another column, representing in the next place, by an excess of barytic chloride, which the number of grammes of cream of tartar which 100 c.c. gives a solution containing the chlorides corresponding to of water, containing 10 per cent alcohol, will dissolve at the sulphates in the ashes, and an excess of barytic the same temperature. These numbers are nearly 57 per chloride. From this solution, properly reduced in volume, cent of those corresponding to pure water. potassium may be precipitated by platinic chloride.

To discover the minimum of alcohol which will render Instead of this series of preparatory operations, to be

a mixture with water incapable of dissolving cream of followed by those required by the nature of the double tartar, a great many experiments were made, and it was chloride, it occurred to me, at first, to treat a small quan- found that the mixture containing 60 per cent of alcohol tity of the low saccharine product by an excess of sulphate fulfils this condition. By bringing all the liquids containof alumina, and, from the quantity of alum obtained, to ing acid tartrate of potassium to the condition of containing calculate that of sulphate of alumina required for the at least 60 per cent of alcohol in volume, I have been able quantity of low products to be treated on a large scale. to obtain the whole potassium in the shape of insoluble This idea afterwards led to that of substituting tartaric cream of tartar. acid for sulphate of alumina, and, on trying tartaric acid, Alcohol of this strength is not, however, to be used the results were so uniform and satisfactory that I was in from the first, as it may in some cases interfere with the duced to apply it to the determination of potassium in solution of the compounds to be analysed, and sometimes compounds of all kinds.

our potassium may be precipitated in other forms than Cream of tartar presents, over every other compound of cream of tartar. It should only be used at the last stage, potassium, the incomparable advantage that, while its immediately before throwing the precipitate on a filter, so solubility is very feeble, the estimation of it, by a titrated that the acid tartrate in solution may be thrown down. alkaline solution, is an operation that only takes a few It should also be used to wash the precipitate on the filter, minutes. To determine the quantity of cream of tartar to free it from tartaric and acetic acid, as we shall see that we may have to analyse it can be placed in a beaker hereafter. glass with a sufficiency of water, which it is advantageous To enable me to explain the method of procedure in to heat, to increase the solubility of the acid tartrate. A estimating potassium as acid tartrate, let ine take the few drops of litmus solution will impart a red colour, simplest case which can present itself, which is the analywhich will persist as long as any cream of tartar remains sis of a solution of pure potassa in water. Suppose we in the solution. If now we add a solution of potassa, ( have a deci-normal solution of potassa, containing drop by drop, to the contents of the beaker glass, the acid | 47 m.grms. of potassa for every c.c. of solution. If we tartrate will be converted to the basic, and, while the drop io c.c. in a beaker glass we may convert the whole change is going on, the unconverted cream of tartar will of it into acid tartrate if we add a sufficient

quantity of continue to colour the litmus red. When the last particle tartaric acid. As to what constitutes a sufficiency, we of acid tartrate has been converted to the basic, an addi- may note that there ought to be enough to precipitate all tion of the smallest particle of potassa solution will turn the potassium to be tested, the minimum being four times the litmus blue. We may now note that the quantity of as much acid as there is potassium in the compound. We potassa added to convert the acid tartrate into the basic is may, however, use a quantity of tartaric acid six times exactly the same as the quantity already in combination greater than the quantity of potassium to be precipitated. as acid tartrate. We may note, moreover, that the equi- Beyond this, in the presence of alcohol, the precipitate is valent of cream of tartar is exadly four times greater apt to contain an excess of acid. I am unable to say in than the equivalent of potassa, so that if we have added what shape this excess of acid exists; but if we use a I grm. of potassa to turn the litmus blue, we must have marked excess of tartaric acid, as much as ten or twelve had 4 grms. of acid tartrate, holding in combination I grm. times more than the potassium to be precipitated, the test of potassa. After every addition of potassa the contents by a titrated solution of potassium will give an excess of of the beaker should be thoroughly stirred, to dissolve the 2 or 3 per cent. If we have any means of getting apportions of acid tartrate which are undissolved, but which proximately at the quantity of potassium in a substance gradually become soluble as potassa is added. Before the to be tested, we should use six times as much tartaric acid change to the basic condition is complete the crystals of | as the supposed quantity of potassium. If, on making the bitartrate disappear, and the red solution becomes per- test, we should find that we have gone too wide of the fectly clear. This is an indication that the end is near. mark, the quantity obtained in a first test will allow us to

That acid tartrate of potassium is so well adapted to determine, to a certainty, the quantity to be used in a

ON THE

CHEMICAL NEWS
Dec. 1, 1876.
Development of the Chemical Arts.

233 subsequent analysis. As every test takes less than an intermingled with the sedimentary rock that it must be hour, both tests together will take up less time than a obtained by mining. The latter deposits are the more single analysis by any other process.

important and furnish nearly the whole of the sulphur of (To be continued).

commerce.

Geology:-The most important sulphur deposits are

those of Italy.* On the main land are the beds of the REPORT

Romagna, which yield yearly 120,000 quintals of sulphur

those of Latera in the province of Viterbo, and those of DEVELOPMENT OF THE CHEMICAL ARTS

Scrofano. Beds of sulphur have also been recently found DURING THE LAST TEN YEARS.*

in the provinces of Volterra, Grosseto, and Avellino.

(To be continued.)
By Dr. A. W. HOFMANN.
(Continued from p. 221.)

QUANTITATIVE ANALYSIS OF COAL
Chlorine, Bromine, Iodine, and Fluorine.

AND PEAT.
By Dr. E. Mylius, of Ludwigshafen.
As an interesting fact we may call to mind that at the

By SERGIUS KERN, St. Petersburg. Paris Exhibition in 1867 large quantities of the silicofluorides of sodium and barium, of soda-ash, and caustic SEVERAL analytical processes have been used by me for soda were displayed by Tessié du Motay as products the estimation of carbon, hydrogen, ash, and sulphur in obtained by the application of fuoride of silicon and various coals, and most of them were found to be very

The hydrofluo-silicic acid on the large scale. The hydrofluo accurate, but rather troublesome in execution. silicic acid was obtained by smelting silicic acid, fluor- following process was used with great success and may spar, and charcoal in a blast-furnace, and receiving in be strongly recommended for laboratories of iron works, &c. water the fluoride of silicon contained in the flue gases,t By this process the work is easily and quickly executed, a process founded on the observations of Bredberg (1829) giving at the same time very accurate results. and Berthier (1835), and elaborated in its details by F.

1. Estimation of Hygroscopic Water. Bothe. I Recently Christy and Bobrownickill have taken out a

3 grms. of the substance in a finely divided state are patent in England for obtaining ammonia from ammonia- small quantity of sand on the bottom of it. The beaker

dried in a porcelain crucible placed in a beaker with a cal waters by means of hydrofluo-silicic acid. They pre is covered with a watch-glass, and the whole is placed on cipitate the ammonia from such water by means of hydro

a sand-bath and heated for about three hours to a temfluo-silicic acid, and decompose the precipitate by means of quicklime without the application of heat. Whether known by the dryness of the watch-glass. The substance

perature of 110°. The end of the operation is easily this attempt to employ a siliceous compound in extensive when dried is weighed, and the percentage of loss is next chemical operations will meet with a better fate than its

calculated. predecessors time alone must decide. It is the first mention of fluorine in chemical technological literature for the

2. Estimation of Carbon and Hydrogen. last five or six years.

The best process was found to be Liebig's :-The The applications of fluorides seem in fact to be ignition of i grm. of coal or peat with lead chromate dominated by some hostile influence. Even the use of (PbCrOd) in a tube of hard glass, 0-25 metre long. The hydrofluoric acid for etching on glass, which appeared resulting carbonic acid, water, and sulphuric acid are secure from rivalry, will probably experience considerable passed through a potash apparatus containing caustic limitation in consequence of an American invention. B. potash (1 part of KHO dissolved in 2 parts of H2O), and C. Tilghmanng uses for etching on glass and other brittle iwo U-tubes, the first containing ignited calcium chloride, materials a jet of sand violently projected against the the second a solution of lead nitrate. The increase in surface of the object by means of a current of air or of weight of the potash apparatus and of the first U-tube steam. (The details of this process are, of course, will show the quantity of carbonic acid and water obtained. strialy mechanical.)

Knowing that carbonic acid contains 27*2 per cent of Against such a rival fluoric acid cannot possibly main carbon, and water II'I per cent of hydrogen, the pertain its ground for etching, especially where large surfaces centage of carbon and hydrogen may be easily calculated. are concerned. It will be restricted to the production of

3. Calculation of the Calorific Power. fine delicate designs, such as the graduation of measuring instruments.

As one part of carbon in burning yields 8080 calorific

units, and I part of hydrogen in burning 34,460 calorific The Sulphur Industry of Sicily. Extracted from the units, the calorific power of the coal may be quickly found.

Report of the Mining Engineer, LORENZO Parodi, [ by Example.-Coal from Donetz Mountains, near the Dr. ANGELO BARBAGLIA, Professor of Chemistry at village Grouchevka, South of Russia :the Instituto Tecnico of Rome.

Per cent.

Carbon Sulphur is a widely diffused element which occurs

580 under the most various forms both in the free and the

Hydrogen combined state. In a free condition it forms rich deposits,

Ash which may be divided into two classes, such as are found

23'0 on the surface of the earth in the neighbourhood of ex

Hygroscopic water

6:0 tinct volcanoes (solfatare) forming earthy strata from 6 to

99'0 10 metres in thickness saturated with sulphur, and underground beds (solfare) in which the sulphur is so intimately For calculating the amount of calorific units in this

coal we proceed as following: * " Berichte über die Entwickelung der Chemischen Industrie Während des Letzten Jahrzehends."

For carbon we have

0'58 X 8080=4686 + Details concerning attempts at the industrial utilisation of hydro. For hydrogen we have

O'I1 X 34460=3790 Nuo-silicic acid will be found in the article on the compounds of silica. # Bothe, Wagner Jahresber., 1868, 265. u Ber. Chem. Gesell., 1873, 1322.

Total calorific units in the analysed specimen 8476 $ B. C. Tilghmann. The sand-blast for cutting hard bodies.

Sull estrazione dello solfo in Sicilia e sugli usi industriali del * This statement must be received with grave doubts. medesimo. Relazione dell ingegnere Lorenzo Parodi al Ministro bable that Iceland contains a very much larger quantity of sulphur d'agricultura, industria e commercia. Firenze, 1873.

Sulphur ..

II'O
I'O

than Italy.-Ed. C.N.

It is pro

an

CHEMICAL News, 234 Action of Water and Saline Solutions upon Lead.

Dec. 1, 1876. 4. Estimation of Ash.

upon this question will be best seen by tabulating the I grm. of powdered coal is heated in a muffle in an open results so as to bring together the quantities of lead platinum dish till all the carbon is burnt off. The re- dissolved by the same liquid acting on a fixed surface, but mainder is the ash which is weighed.

under varying conditions of exposure to air.

This is done in Table II. 5. Estimation of Sulphur.

I have not tabulated the whole of the results here, 0.5 grm. of powdered coal is heated with a mixture of but only those which are dire&ly comparable with one 15 c.c. of HCl and 5 c.c. of HNO3 for about one hour, and another. next left for 12 to 15 hours on a sand-bath. The liquor is 6. It is scarcely admissible from these experiments to filtered on a strong double filter to prevent the coal-dust conclude that exposure to air invariably causes passing into the filtrate. The sulphur is precipitated from increase in the quantity of lead dissolved. As in the conthe filtrate by barium chloride. The solution is left quiet sideration of the influence of surface exposed, it was for half an hour and is next filtered; the precipitate of found to be difficult, if not impossible, to eliminate other Baso, is washed, dried, and then weighed. Supposing circumstances which modified the action, so here we 0'5 grm. of coal to be used for the analysis, every appear to have many conditions tending to overshadow 0.001 grm. of barium sulphate obtained is equal to o'02 per the effects of that one which it was especially desired to cent of sulphur.

study. If we compare the quantities of lead dissolved in Obouchoff Steel Works,

corked flasks and in open beakers, the action appears to St. Petersburg.

be greater in the former than in the latter cases, until we come to deal with actions allowed to proceed during con

siderable periods of time, and upon somewhat extended PROCEEDINGS OF SOCIETIES. surfaces of lead. When the surface exposed extended to

50 sq. cm. (to 500 cbc. of liquid) and the time of action

amounted to 300 to 500 hours, the exposure of the surface MANCHESTER LITERARY AND PHILOSOPHICAL of liquid to a considerable surface of air invariably SOCIETY.

increased the quantity of lead dissolved in a given time.

In these experiments the surface of liquid exposed to Ordinary Meeting, October 3rd, 1876.

the air was increased from about 2 to about 100 sq. cm. "On the Action of Water and Saline Solutions upon or beakers and in open basins we find that there is in

By comparing the quantities of lead dissolved in flasks Lead," Part II., by M. M. Pattison Muir, F.R.S.E., variably a very marked increase in the latter cases. The Assistant Lecturer on Chemistry, Owens College.

increase here also becomes more marked when the action (Concluded from page 225).

has been allowed to proceed for tolerably extended 5. Does free admission of air to the surface, or passage periods of time. of air through the body of the liquid influence the quan- In these experiments the surface of liquid exposed to tity of lead dissolved? The bearing of the experiments the action of air increased from about 2 to about 170 sq.cm. A.-Liquid employed, Distilled Water.

B.-Liquid employed, Distilled Water.
Total Lead (in Mgms.)

Lead Dissolved.
Surface Dissolved after-
Description of Vessel.

Vessel.

Surface.
of Lead.
Hours.

Hours.
336

336 Corked flask

25
07

I'5
Flask

50 07

0'9 Beaker half filled with

water 11'5 cm. diam.
at mouth
0'4
Beaker

04

1.8 Basin, 14:5 cm. diam.

0.6
20 4'2
Basin

0.8

I'5 395 Flask with air passed through

1'5
C.-Liquid employed, Potassium Nitrate,

D.-Potassium Nitrate, o‘20 grm. per Litre.
O‘20 grm. per Litre.
Flask

25
0'7
1.6 Flask

50

1'5 Beaker

0:4 0'5
Beaker

0.6

2'5 Basin

0.8

2.8 6.0 Basin E.-Calcium Chloride, 0'20 grm. per Litre.

F.-Calcium Chloride, o‘20 grm. per Litre.
Flask
25

3'0
Flask

50

2'5

2'5 Beaker I'31'5 2:8 Beaker

2'03'0 Basin

20 30 595
Basin

25 3'5 Flask with air

3'5 3'5 3'5
Flask with air

0*505
Beaker-lead partly sus-
pended in liquid, partly

Beaker-lead partly sus. in air

1'4 2'5 35
pended in air

3'5

4'0 G.-Potassium Carbonate, 0'20 grm. per Litre.

H.-Potassium Carbonate, o 20 grm. per Litre. Flask

25
traces o'3

0'3
Flask

50
traces o'3

0'3 Beaker

0'3
03
Beaker

0'3

0:3 Basin

0-5 0'7

07
Basin

07 099 0'9 Flask with air

0.6 Flask with air

05 0'5 0'5 Beaker-lead partly suspended in air

traces o'2

0-3
Beaker-lead partly in air

Oʻ5 07
I.-Ammonium Sulphate, oʻ20 grm. per Litre.

J.-Ammonium Sulphate, o 20 grm. per Litre. Flask

25
Oʻ5 07 0'7
Flask

50
0'7 07

07 Beaker

0'7

I'3
Beaker

07

195 Basin 2'5 90 16'o ? Basin

2'5 7'5

- ?12'0 Flask with air

I'3 3'0 5'0
Flask with air

07 13 2'5 Beaker-lead partly in air

2'5
Beaker-lead partly in air

3'5

42

168

505

42

168

340

340
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Dec. 1, 1876.
, } Action of Water and Saline Solutions upon Lead.

235 It may be that the relation between lead exposed and before I can permit myself to generalise with safety, and total quantity of liquid influences the action of the air these experiments must be conducted on a larger scale upon the metal; this point I propose to examine in a before the results obtained can be applied to the actual further communication. The passage of air through the conditions which influence the mutual action of water and various liquids certainly caused an increase in the quan- lead in our domestic water supply. tity of. lead dissolved as compared with those quantities 9. By comparing the absolute quantities of lead disfound when the action was allowed to proceed in closed solved as stated in the foregoing, tables with those flasks; nevertheless, in every case-with one exception- tabulated in the former papers and obtained under some. considerably smaller quantities were dissolved when air what comparable circumstances, it is apparent that the was passed through the liquids, than when large surfaces present numbers are much smaller than the former. This of liquid were merely exposed to the action of the super- I believe to be due to the chemical purity of the lead incumbent air.

itself. In former experiments I made use of ordinary I have already pointed out, when considering the influ- sheet lead; in the present experiments what is sold by ence of the extent of surface of lead exposed, that the the chemical dealer as “pure lead” was employed. I only experiments in which a constant increase in lead believe that many contradictory results noticed in the dissolved (independent of the salt in solution, the time, numbers obtained by different experimenters on the sub&c.) was noticed, were those in which the lead was ject of the action of water on lead can be traced to slight partially suspended in the liquids and partially surrounded differences in the purity of the lead employed by them. by air, the liquids being contained in beakers and exposing ! purpose to examine this subject quantitatively, and a surface of about 100 sq. cm. to the surrounding air. If hope, on a future occasion, to lay the results before the we compare the quantities of lead dissolved under these Society. conditions with the quantities dissolved in experiments carried out in a precisely similar manner, except that the lead was wholly surrounded by liquid, we find that there was a small but constant increase in the former cases ;

NOTICES OF BOOKS. the quantities dissolved in these cases were not so large as those which passed into solution when the experiments were carried out in basins and the lead was wholly im Report on the Ventilation of the Hall of Representatives mersed in the liquid. On the whole, then, the exposure of

and of the South Wing of the Capitol of the United the various liquids to a large surface of air appears to

States. By R. BRIGGS, C.E. Philadelphia : H. B.

Ashmead. cause an increase in the quantity of lead dissolved ; this increase becomes specially marked after the lapse of con- What can be simpler, theoretically speaking, than ventisiderable periods of time.

lation ? Air as it is contaminated by the products of 7. Do the solvent actions of dilute saline solutions upon combustion and of respiration, and by the effluvia from lead continue during lengthened periods of time, or is the bodies of animals, is heated pari passu. Now, as there a limit reached after which little or no further action gaseous matter under such circumstances expands and is exercised upon the lead ?

becomes specifically lighter, the foul air has a tendency By consulting the two tables it becomes very evident to ascend, and all we have to do is to make two apertures, that so far as these experiments allow one to judge there one at the top and the other at the bottom of the building, is a constant increase of lead dissolved with increase of when, heigh! presto! the foul air will escape from the time of action, except in the case of those solutions which former, whilst fresh pure air will rush in from below and contain carbonate of potassium. This increase appears take its place. Yet this system, so admirable in its broad to be proportionately greater in the case of those salts theoretical outline, in practice will not work at all. The (nitrates, &c.) which aid the solvent action, than of those aperture in the roof of the building made for the ascent of which tend to stop the solvent action of water upon lead the impure air becomes the battle ground of contending This increase is also greater for equal time-intervals, currents. Sometimes the rising stream flows out un. when a large surface of liquid is exposed to the surround checked and then again the cold external air forces its ing air than when a small surface is so exposed. The way down upon the heads of the inmates. Nor is it increase was not very marked when the experiments were actually true that foul air is always and necessarily heated. conducted in flasks, through which a stream of air was The "ground gases,” which Prof. v. Pettenkoffer has constantly passed.

brought to our knowledge, are no less dangerous than the The exception which I have made in favour of potassium effluvia from living animals, but their temperature is low carbonate, when laying down the general rule, that in. and they ooze into houses and public buildings from crease of duration of action increases the quantity of lead beneath. Hence, wherever a large number of persons are dissolved, requires explanation. On examining the actual likely to be collected together, as in churches, theatres, numbers obtained it is evident that the amount of lead courts of justice, legislative halls, &c., special arrange. dissolved by liquids which contained potassium carbonate ments are required for the construction and adaptation of did increase as the action proceeded, up to a certain which sound physical knowledge is required. Even when point; this increase was, however, very slight, and after eminent authorities have been consulted and expense has the expiry of 340 hours it ceased. Hence, I conclude pro- been incurred without limit the result is frequentiy far visionally that in the presence of this salt the solvent from satisfactory. Some of us may yet remember the action of water upon lead soon-comparatively speaking verses in Punch beginning :-“This is the house that -reaches a maximum. I intend to investigate this subo Barry built." ject more fully in a future communication.

According to the view taken in the pamphlet before us & In conclusion, it appears to be shown by these the allowance of air per minute for each individual in a experiments that the solvent action of dilute saline solu. public building may range from 30 cubic feet in winter to tion upon lead tends to attain a maximum when large 100 cubic feet in summer. This supply in a hall like that surfaces of liquid are exposed to the surrounding air, and of the American House of Representatives, which may at when the volume of liquid_ is large in proportion to the times contain 1600 persons, will therefore range from surface of lead exposed. Further, that under these con. 50,000 to 100,000 cubic feet per minute. In many inditions, and in the presence of those salts which aid the stances there is some difficulty in selecting a suitable action-especially nitrates, and more especially am- place whence so large volume of air may be safely monium nitrate-the quantity of lead dissolved increases drawn. If the opening be near the surface of the soit in an increasing ratio with the time during which the ground air," sewer gases, emanations from “mada action is allowed to proceed.

ground," and from putrescent matter of all sorts and dust Many experiments must, however, be .yet carried out may be sucked in. Nor is the summit of a tower any

236
Anthracene Production.

CHEMICAL NEWS,

Dec. 1, 1876. great improvement. The authors of the report before us and the summer term to the organic department. There remark :" The elevated air is more impure when the is a "chemical colloquium" of one hour weekly, for the stratum of diffused chimney exhalations is reached, than purpose of impressing the more important points of pure it is below. The Londoner does not experience any great chemistry upon the students. Dr. Classen gives instrucsense of purity of air from the top of St. Paul's as a tions in analytical chemistry two hours weekly, and the general rule; and the haze of any large city is perceptible analytical department of the laboratory is open daily, exfor miles on a still day-the entire city is covered as with cept Saturday, for seven hours, under the superintendence a blanket by an ascending and dispersing cloud, and of Prof. Landolt, and Drs. Classen, Brühl, and Clören. receiving its fresh air from beneath from all sides." In Prof. Stahlschmidt gives weekly four hours' instruction in the American Capitol the air is drawn from the level of technological chemistry, and four hours in the construcan elevated terrace, some 30 feet wide and 35 feet in tion and arrangement of chemical manufactories, and, height, beyond which lies a park, 800 to 1000 feet in with his assistants Drs. Böckmann and Scheele, superinwidth, carefully drained, and, as a matter of course, free tends practical work in the technological laboratory daily, from nuisances. A more favourable locality for drawing except Saturday. Dr. Brühl lectures twice weekly in the a supply of pure air could not well be selected. But when summer term on theoretical chemistry. Dr. Landolt gives a proper source of fresh air has been found its introduc. practical instructions in saccharimetry. Dr. Classen gives, tion into the room involves two questions which may lead in the summer time, one lecture weekly, on chemical juto four different systems. Are we to adopt the" vacuum" risprudence and toxicology, and in the winter term on the or the "plenum" method ? In other words, are we to determination of the illuminating power of gas and its draw the foul air out or to force the fresh air in? A little technological analysis. Prof. Stahlschmidt lectures weekly consideration will show that the latter or plenum method on brewing and on the manufacture of beet-root sugar. is decidedly preferable. If we suck out the foul air, other Dr. Böckmann delivers two lectures weekly on dyeing and air will stream in to supply its place, not merely from our calico-printing, and two on stechiometry. In addition to carefully selected source of a supply, but from every con- all these facilities the students have the opportunity of ceivable quarter. We shall suck in "ground gases” from visiting different chemical works in the surrounding the soil beneath and through the foundations. The next country. We commend these complete and thoroughquestion is whether we are to introduce pure air from going arrangements to the careful consideration of the above or from below? If we select the former method authorities of our new colleges in Leeds, Newcas:le, Birour descending, stream of pure air meets the stream of mingham, and Bristol. contaminated air arising from the persons of the occupants, and the latter current, instead of being withdrawn as quickly and quietly as possible, is beaten back upon the inmates, and runs a great risk of being inhaled over again. The method actually adopted in the Hall of Representatives is

CORRESPONDENCE. the plenum from below. As a matter of course the temperature of the in-flowing current requires to be regulated. By means of a system of steam-pipes it is kept at the

ANTHRACENE PRODUCTION. uniform heat of 70° F., which is found most conducive to the comfort of those present in the building. The fresh air enters through vertical gratings in the steps of the

To the Editor of the Chemical News. platforms, upon which the seats of the members are Sir,-In your journal of the 17th inst. is published an placed. The reason why horizontal gratings in the floor article on “ Anthracene Production," by Dr. Frederick were not adopted is somewhat singular.

Versmann, in which the balance-sheet of the Chemische “ The nearest approach to a uniform distribution would Industrie Actien Gesellschaft of Elberfeld, as recently pub. of course have been attained by the perforated floor and lished, is referred to in the following manner :porous carpet of the House of Lords, England, but the

"In Germany all public companies are very properly habits of our people in use of tobacco put this method out compelled by law to publish their annual balance-sheet of the question."

in at least three newspapers, and such document-pubWe learn from the Appendices that the arrangements lished only on the oth inst., in the Cologne Gazette--by for the ventilation of the Hall of Representatives, though the Chemische Industrie Actien Gesellschaft zu Elber. originally well designed and efficient, have not been in feld,' formerly Gessert Brothers, tells its own tale in a all points maintained in thorough working order. The few figures. "This official document informs the sharebest systems in ventilation, as in everything else, are of holders that the loss of the twelve months' working, little avail unless they are carefully attended to. The ending at Midsummerlast, amounts to £40,000 ; and as this authors conclude with a significant reflection :—“The dismal statement is merely a repetition of previous equally truth is, all our heating and ventilating appliances are a compromise of conditions-a truth extending beyond all doubt that at next month's general meeting the Company

unsatisfactory balance sheets, there seems to be little mechanical operations to the phenomena of nature will be wound up, and that very likely the whole capital herself.” On this we may all meditate with advantage.

amounting to some £180,000—will be lost.”

By request of the Chemische Industrie Actien Gesell

schaft of Elberfeld we now beg to hand you a true copy Programme of the Royal Rhenisk-Westphalian Polytechnic of the said balance-sheet, from which you will see that the

School of Aachen, for the Course 1876-77.* Aachen: figures given by Dr. Versmann are inaccurate and his J. J. Beaufort.

observations most unjustifiable. On a former occasion we have called attention to the ad this amount is the actual loss during the past three years,

The profit and loss account is debtor about £40,000, but mirable arrangements of this college for the study of and not during one year. The capital of the company is applied science, and we find that they are still maintained £150,000, not £180,000. in full efficiency. As an instance of the combined tho- Dr. Versmann takes upon himself to say that at the roughness and many-sidedness evinced in the culture of next general meeting of the company “very likely the science, we may briefly describe the chemical course : whole of the capital will be lost." Dr. Landolt gives six lectures weekly on experimental As Dr. Versmann bases his remarks upon the figures chemistry, the winter term being devoted to the inorganic given in the balance-sheet, we refer you to that document,

which describes the position of the company on June 30, * "Programm der Königlichen rheinisch-westfälischen Polytech- 1876, as under :nlichen Schule.

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