This plan is troublesome and inconvenient. If partiNEWS.cular care is not taken to wash the sulphuret of iron with water and weak carbonate of soda, and drying it well before putting it away, it will be found oxidised and useless when wanted.

returns to the bottle B when the apparatus is not in

use.

To generate sulphuretted hydrogen with this apparatus, we may observe that if the tubes by which the bottle A communicates to the bottle B are full of liquid, it will merely be necessary to open the screw pinchcock D, which will remove the pressure from the bottle A and allow the dilute sulphuric acid in bottle B to flow into bottle A. If these tubes of communication, including the flexible tube, are not full of liquid, the screw pinch D should be kept open, and air be driven into the bottle B from the mouth through the tube E by opening the pinchcock C. The pressure exerted in this way on the surface of the bottle B drives the liquid it contains into the tubes of communication, and, after the blowing of air through the tube E has ceased, the liquid continues to flow into A until it reaches the sulphuret of iron, when sulphuretted hydrogen is given off.

On account of the offensive nature of the gas, care should be taken not to draw air from the bottle B into the mouth. This is easily avoided by filling the mouth and lungs with air before blowing into the bottle B. If care is not taken to open the screw pinchcock D before blowing, the gas in the bottle will not be driven forward, but will be mixed with the air from the lungs, and partly find its way into the mouth of the operator. This screw pinchcock D is specially useful in regulating the outlet of sulphuretted hydrogen, and consequently its produs ion.

When no more gas is wanted the screw pinchcock should be closed entirely, after which a certain pressure is produced in the apparatus from the gas which continues to be formed. After a minute or two the pinchcock C should be opened to remove the pressure from B, and allow, not only the liquid in A to flow back into B, but also a certain quantity of gas, by which means the liquid connection between the two bottles is interrupted, and remains so while the apparatus is not in use.

471, Lafayette Avenue, Brooklyn, December 20, 1875.

the point B, but without sufficient force to break the tube. The inflow of mercury is regulated by the clamp D. When full the barometer can be safely disconnected with a little care, and the excess of mercury poured out. For filling straight tubes the part A can be bent and connected to the barometer inclined downwards. It is almost needless to add that the barometer during the filling must be supported by a clip or otherwise.

A

ON THE USE OF THE SPRENGEL VACUUM
PUMP FOR FILLING BAROMETER AND
THERMOMETER TUBES WITH MERCURY.
By ERNEST FRANCIS,
Government Laboratory, Trinidad, B.W.I.

THE difficulty of filling tubes with mercury so that air may be excluded is well known, and instruments in which this condition is attained are highly prized. The ordinary process of filling barometers by boiling is tedious and unsatisfactory, more especially to those unused to the operation.

It has been found that the improved form of the Sprengel pump affords an admirable means of accomplishing the operation, and adds another to the numerous good qualities for which the instrument is famed. The process is easy and would enable barometers to be filled in the laboratory with perfect accuracy. It has the additional advantage of being applicable to tubes of any calibre.

The operation is performed by connecting and exhausting the barometer tube; the outflow orifice of the pump being then stopped, mercury passes in and fills the exhausted tube.

Further details may be gathered from the accompanying diagram, but the arrangement would vary slightly with the shape of the tube to be filled. The diagram shows a Bunsen's syphon barometer, connected to the pump at A by vulcanised tubing, with the joint surrounded by a tube filled with mercury. After exhaustion the end of the pump C is closed either with the finger or by a specially furnished clamp or stopcock. The mercury which is kept flowing from the reservoir then ascends and completely fills the barometer. The mercury falls over the bend to

OF this long and valuable memoir we can only insert a few portions:

If we compare all the facts it appears as the final result that the meteoric silicates and iron masses have been formed simultaneously in the moist way, and the iron by reduction effected by organic bodies. The reasons for this view are as follows:

1. The silicates contain small quantities of water. 2. The silicates decrease in specific gravity by strong heating and fusion.

3. Different silicates are crystallised together; some parts being soluble in hydrochloric acid, and other parts are not, as in basalts and phonolites.

4. The olivin, containing protoxide of iron, is green, and not black.

5. The igneous crust is black in contradistinction to the interior of the meteorite.

6. Certain meteorites contain organic bodies, analogous to terrestrial hydrocarbons.

7. Meteoric iron contains no chemically combined carbon, even when graphite is present.

8. The sulphide of iron is contained in single particles distinct from the iron, and not diffused through the whole

mass.

9. Schreibersite, composed of phosphorus, iron, and nickel, is likewise found in distinct particles.

10. Brittle meteoric iron becomes soft by ignition if no sulphide of iron is present.

11. Malleable meteoric iron, containing sulphide of iron, becomes hot-short on fusion.

12. Meteoric iron, if heated to whiteness in a vacuum, evolves hydrogen.

13. The "Figures of Widmannstätt" give proof of an undisturbed crystallisation.

14. No silicium is present which agrees with theory, since silica cannot be reduced by organic bodies.

The author here solicits possessors of meteorites to forward him small fragments, &c., of no value as specimens, for the purpose of extending his observations. He next proceeds to the question of the origin of meteor

ites.

The view formerly maintained that they were projectiles from the moon, in which it was supposed that volcanoes were recognised, is quite untenable. It is fatal to this theory that the meteorites coincide with the periodically recurring swarm of shooting stars, which have a planetary orbit in space, and also, that, as appears from the above, they display no igneous structure, and cannot, consequently, have sprung from a volcano. That such things can have been formed in the air is a notion* built of air. The constituents of meteors, such as olivin, augite, anorthite, and their organic matter prove that these bodies must have been formed upon a planet, warmed by the sun, or by a sun in absolute rest, and in the lapse of an enormous length of time, like the terrestrial silicates. Under what circumstances this planet has been shivered in fragments does not appear. It must have had a large collection of waters, a sea, which has likewise been dispersed, and which now is to be found in meteoric swarms, and in comets, as already shown.

The author maintains with Galle and Förster (see Pogg. Annalen, 148, 172) that the shooting stars of November 27, 1872, consisted of particles of Biela's comet, whose orbital plane was intersected by the earth at that precise time, and whose direction agreed within a degree with that of the meteors.

It is striking that such cosmic bodies as we can take in hand and examine, namely the earth and meteorites, show not the smallest trace of an igneous formation if we regard volcanoes, and the fiery crust of meteorites as subsequent modifications, and not as original features.

The peculiarity of meteorites as compared with our globe, consists in the circumstance that we find in the former more products of reduction, and except the earths, no perfect oxides. Thus in meteorites we find no ferric oxide, but metallic iron, sulphide of iron, and phosphide of nickel-iron. Upon our globe phosphorus occurs only as phosphoric acid. Hence the hypothetical planet where the meteorites originated must have been smaller than our globe, and have had a less dense atmosphere containing less free oxygen. The sp. gr. of most meteorites, 3275, agrees with the calculated density of the planetoids between Mars and Jupiter.

Dr. Mohr does not accept the view of J. R. Meyer that the heat of the sun is maintained by the infall of meteorites. He considers that in an infinite universe, filled with radiating suns, our sun can lose nothing which it does not receive back every moment from its fellows, since the void space of the universe has been for infinite ages filled with that sum-total of rays which it is capable of receiving.-Liebig's Annalen der Chemie.

"Aus der Luft gegriffen,"-a common German phrase for any view lacking a substantial basis.

REPORT
ON THE

DEVELOPMENT OF THE CHEMICAL ARTS
DURING THE LAST TEN YEARS.*
By Dr. A. W. HOFMANN.

(Continued from p. 58.)

FOR the generation of cold by evaporation liquids are most suitable which require a technical preparation and possess a considerable value. In the manufacture of ice on the large scale it is therefore needful to restore the escaping vapours to their original condition, i.e., liquids capable of re-evaporation so that a given quantity of material may serve again and again, circulating continually. This restoration can be effected by two processes different in form and action of which the ether machine and the ammonia machine are respectively almost the sole existing representatives.

The ether machine is arranged as follows:-A doubleaction air-pump worked by some especial source of power (generally a steam-engine) draws incessantly the vapour of ether out of a vessel filled with liquid ether (ice-generator or evaporation-receiver.) By the return of the piston the vapour is compressed and driven into a worm cooled by water. As the vapour which has been heated by compression cools, it condenses to a liquid which is collected in a suitable vessel whence it is driven by the pressure of the condensed vapour back into the evaporation-receiver where it recommences its function.

The principle of the ether machine was patented in England by Jac. Perkins, of London, as early as 1834. His apparatus contains all the parts requisite for continuous action-evaporation-receiver, air-pump, and worm-condenser. The first-mentioned part, according to the drawings, consists of a vessel like a boiler formed of two segments of a sphere and surrounded with water. This arrangement is not very suitable, possibly the reason that nothing further has been heard of the development of the apparatus. Or, possibly the time was not yet come for the utilisation of the principle, the demand for ice being not important enough to render it a remunerative business.

The next patent for an ether ice machine was taken out in 1856 by John Harrison, of Geelong, in Victoria. In September, 1857, he obtained a patent for improvements, according to which latter the machine is arranged as follows:-The evaporator has the form of a horizontal tubular boiler, with numerous narrow tubes. Through these tubes a concentrated solution of common salt which is pumped up at the top streams down in a zigzag direction, the tubes being divided in three sets from above downwards. The ethereal liquid streams out of the condenser into the boiler outside the tubes. The solution of common salt passes from the boiler into a long tank in which are suspended vessels of the water to be frozen (ice-boxes), passes through it, and is pumped up again into the boiler. The arrangement is perfectly rational. Harrison states in his specification that he can, by means of his machine, produce a temperature of 29'; but from an economical point of view he prefers -2° to -5°. The process of freezing is then slower, but the expenditure of power is much less, and the ice is transparent like natural ice. At the end of the year 1859 Lawrence established works at Liverpool for the production of artificial ice, and sold it at one halfpenny per lb. Dullo+ and Grünberg have described the process, the latter with illustrations. From 40 to 60 cwts. of ice were prepared daily by means of a steam-engine of 15 horse-power. In 1860 Laboulay§ described an ether ice machine by F. Carré, of Paris. In

"Berichte über die Entwickelung der Chemischen Industrie
Während des Letzten Jahrzehends."
+ Dullo, Dingl. Journ., elviii., 115.

# Grünberg, Pol. Centralbl., 1863, 656.
§ Laboulay, Buil. Soc. d'Enc., 1860, 129.

it the ether acted directly upon the water to be frozen.*, the latter in the air it is partly transformed into vanadic It was soon abandoned by Carré after he had succeeded in carrying out the ammonia machine, which is far more efficacious. In March, 1862, Dr. Siebe, of Lambeth, obtained an English patent for an improved ice machine. The general arrangement is the same as Harrison's. The boiler, instead of being horizontal, is vertical. There are also changes in the air-pump and the cooler, which do not affect the principle. The ice-boxes are so arranged that when the first one, which is exposed to the influx of the cold liquid, is frozen and taken out the entire series slides forwards, and the new box filled with fresh water comes in last. From this date we find Siebe's name alone connected with the machine in question, which, however, is still spoken of as Harrison's principle. Siebe's machine figured at the London Exhibition of 1862.

(To be continued.)

THEORY OF THE

PRODUCTION OF ANILINE-BLACK BY MEANS
OF THE SALTS OF VANADIUM.

By M. A. GUYARD (HUGO TAMM).

SINCE the interesting discovery of M. Pinkney is known it may be permissible to say a few words on the question of the formation of aniline-black, hitherto obscure, but which the reaction of the salts of vanadium completely

elucidates.

acid. On the other hand, if vanadous chloride and chlorate of potassa are brought in contact, the latter is decomposed with disengagement of chlorine, and the vanadous oxide is transformed into vanadic oxide. Reciprocally, if we introduce vanadic oxide, or an alkaline vanadate, into hydrochlorate of aniline, the vanadous oxide is instantly reduced to the state of vanadous oxide or chloride. If we introduce into a mixture of an aniline salt and of a chlorate 1-1000th of vanadous chloride or of a vanadate aniline-black is produced with the same energy. In fact, in the twofold contact with the oxidising salt and the reducing organic compound the vanadium passes with the speed of an electric spark from the state of | vanadic acid to that of vanadous oxide, and reciprocally as long as there remains a trace of aniline to oxidise or of chlorate to decompose.

In order that a metal may aid in the production of aniline-black it must possess at least two degrees of oxidation in the moist way. Thus potassium, sodium, lithium, calcium, magnesium, barium, aluminium, zinc, cadmium, lead, silver, and all analogous metals, are incapable of taking part in the production of aniline-black.

But if a metal has two stages of oxidation in the moist way, it must not pass with too great facility from one of these states to the other.*

Thus protochloride of tin is improper for the preparation of aniline-black. In fact this salt absorbs oxygen and chlorine with such avidity that it decomposes a certain quantity of chlorate of potash, but it absorbs the products of the decomposition, and does not yield even the smallest If we introduce into a normal mixture for aniline-black, portion to the aniline. We may thus, at pleasure, retard made up of water 100 grms., hydrochlorate of aniline 8 grms., the formation of aniline-black, even in mixtures containing chlorate of potash or soda 35 to 4 grs., about 1 centigrm. till all the tin is peroxidised, and when the black makes vanadium. The formation of aniline-black does not begin of vanadous chloride or vanadate of ammonia, we see with surprise the liquor darken in a few moments, and its appearance it can be made to disappear again by adding then gradually deposit an abundant precipitate of anilinefresh quantities of the protochloride of tin. If we take black. After about forty-eight hours the reaction is nearly the higher oxide of a metal having two stages of oxidation complete, and the liquor is taken up in a thick paste, vided that the salt passes readily to the lower oxide. we may produce bodies analogous to aniline-black, proalmost solid, in consequence of the formation of almost all the aniline-black which it is able to furnish. This reThus, permanganate, bichromate, ferrate of potassa, and action is so delicate that I part of vanadous chloride transbivanadate of ammonia form with hydrochlorate of aniline forms 1000 parts of hydrochlorate of aniline into anilinebodies analogous to aniline-black, and that without the black, and that in practice 500 parts may be thus advan-intervention of chlorates. Alkaline tungstates and molybtageously transformed by 1 part either of the chloride or dates are not favourable to the production of blacks. If of the vanadate of ammonia. This important discovery we take the lower oxide of a metal having two stages of renders dyeing with aniline-black as easy as printing, and oxidation we may, in presence of chlorate of potash, nothing can equal the beauty of the blacks thus obtained. obtain aniline-black. The lower oxides of cerium, iron, Since the discoveries of Lightfoot and Lauth there is no and manganese are here included, as well as those of reaction which is calculated so much to generalise the use nickel, cobalt, and chrome. These latter become perof aniline-black both in dyeing and printing. oxidised with difficulty, and are not very fit for the purpose, but in presence of 1-5000th of a salt of vanadium they aid in the formation of black.

But this reaction is chiefly interesting in a chemical point of view. It is one of the most elegant reactions of chemistry. The author thinks he may give its true image by saying that the vanadium is a fluid spark which determines the combustion of the fluid mass of salts of aniline and of chlorate. We make aniline-black by means of a drop of a salt of vanadium, just as we set fire to fuel by means of a match. The power of the vanadium salts in the production of aniline black is more than a thousand times greater than that of copper. The reason of this is intelligible if we know the properties of vanadium. There is no metal which passes more readily from the lowest to the highest stage of oxidation and returns again to the lowest. Under the feeblest reducing influences vanadic oxide becomes vanadous oxide, and under the faintest oxidising influences vanadous oxide is re-converted into the vanadic. This is the whole secret of the power of vanadium-a power so great that the author thought at first he had encountered a new force, or at least one of those mysterious agencies named catalytic; but a closer study of the phenomenon soon led to its explanation. In fact, on dissolving vanadic acid in hydrochloric acid it is transformed into vanadous chloride, and on evaporating

* Dingl. Pol. Journ., clviii., 109.

The lower oxides of uranium, tungsten, and molybdenum, yield alone very fine blacks. But the higher oxide of uranium, like the tungstates and molybates, does not act. When the salts of uranium seem to form black, as M. salt of uranium has been obtained from a pitch blende Pinkney considers that he has observed, it is because the containing vanadium.

Copper passes readily from the maximum to the minimum state of oxidation, and still more readily in the inverse direction consequently, next to vanadium, it is the metal best suited for the production of black, and the one generally employed.

The quantity of salt of vanadium necessary to transform aniline into black is so small that it may be practically disregarded. Hence we infer that metallic salts, though necessary in the formation of aniline-black, do not enter into its constitution. Aniline-black with vanadium is identical with aniline-black with copper, the one containing no vanadium, and the other no copper.

M. Coquillion states that he has obtained aniline-blacks

*This seems scarcely consistent with the previous passage, where the author states that "no metal passes with more facility from the minimum to the maximum state than vanadium."