Graphite may be isolated by the following method:A few grammes of metallic powder are projected into fused potash, and thus a mixture of nickeliferous iron and graphite is obtained. This mixture may be treated in several ways.

Ist. Iron is dissolved in chlorhydric acid, which leaves as residue the graphite almost pure.

This

2nd. The graphite is separated by lixiviation. process presents the advantage of giving both graphite and nickeliferous iron; but the separation is never complete. 3rd, and lastly. The magnet may be employed only when the graphite is abundant; in other cases it is drawn up with the metal.

In all cases the residue is washed by chlorhydric acid to dissolve foreign matters, such as troïlite and schreibersite, or what results from their being attacked by fused alkali.

The graphite extracted from the Caille iron shows a density equal to 1715. Its analysis gave

The graphite is remarkable on account of its great unalterability.

VI. EXTERNAL CRUST.

The portions of meteoric iron, upon which is the crust, being separated by means of a saw, they are placed in a concentrated solution of bichloride of mercury. After a sufficient time all metallic particles are dissolved, and the oxides, amongst which is the crust, remains alone.

Usually there is with it the products of its alteration by However, the crust is still mixed with foreign matters schreibersite, troïlite, and stony grains may be also mixed atmospheric agents, and particularly limonite. Some with the principal substance, and their separation is very difficult.

troilite; stony grains remain as residue after the action Weak chlorhydric acid carries away limonite and of the magnet; lixiviation permits the purification of the crust from schreibersite.

Besides, these operations may be simplified by choosing the portions of the crust that seem almost pure. They frequently detach themselves from the subjacent metallic

matter.

These numbers agree with the formula Fe2O3, (FeNi)O, which does not differ from that of magnetite, except by the substitution of a small portion of nickel for a corresponding quantity of the iron of the protoxide.

It is remarkable that, if in Pugh's analysis we only consider sesquioxide of iron, protoxide of iron, and protoxide of nickel and of cobalt, we arrive at numbers very near to those required by the above formula.

VII. STONY GRAINS.

Several of the operations described above may evidently serve to prepare the stony grains in a state of purity. But this is how the separation must be made when it is especially intended to obtain these grains.

the air in a concentrated solution of bichloride of mercury, Iron in form of lumps is left protected from the contact of and frequently stirred. After a sufficient time the metal disappears, and the liquid contains stony grains mixed with protochloride of mercury, and generally with a small quantity of metallic mercury. There is also troïlite, schreibersite, and graphite. A solution of chlorine carries

If the stony grains (as is the ordinary case) are not oxidisable, hydrogen may even be replaced by air, which burns the carbon and gives directly the stony grains perfectly pure.

These grains are of different composition, and it appears that there exists a certain relation between their composition and their situation. Some are localised in the iron; others are situated in the troïlite, or, perhaps, in the graphite which surrounds this sulphur. The grains of the first category may be found in meteoric irons of Tazewell and of Tuczon. They are formed of peridote, which is proved by the analyses published by Mr. Lawrence Smith. I have studied those grains, and found that their density is equal to 3.35. I have not observed crystalline forms.

The grains of the second category were given by the troîlite of the Caille iron. Their quantity was too small for me to be able to analyse them, but I have submitted them to the blowpipe assay. Those grains are not fusible, and gave nothing but the reaction of silica. The troilite of Charcas iron gave me analogous results.

VIII. GASES.

Gases have been recognised in the meteoric iron of Lenarto, by M. Boussingault and by Mr. Graham.

I have sought the same bodies in another iron of the same origin by means of the solution of those masses in concentrated bichloride of mercury. The results were that gases do not exist in appreciable quantity in the irons of Caille and of Charcas. The mass of Krasnojarsk (Siberia) gave me a small bubble of gas, having the composition of atmospheric air; but it must be remarked that this iron was cracked.

IX. RARE SUbstances.

In concluding this enumeration, I must mention chromite and protochloride of iron, which appear in certain irons. Their separation is evidently easy, and their composition is identical with that of analogous terrestrial compounds.

After having described the methods which have permitted me to separate in a state of complete purity the immediate principles of meteoric irons, I will remark that those methods can be employed to estimate the relative quantity of the substances in question.

I have, for instance, submitted to a quantitative immediate analysis the meteoric iron discovered in 1784, at Xiquipilco, in the valley of Toluca (Mexico), and I have found in it

Nickeliferous iron

ON THE

EXHIBITION OF COHESION FIGURES TO A LECTURE AUDIENCE.

By C. J. WOODWARD, B.Sc., Lecturer on Chemistry and Physics, Midland Institute, Birmingham. WISHING to exhibit the singular figures discovered by Professor Tomlinson, and known as cohesion figures, I proposed adopting the method mentioned by Mr. Reynolds in the CHEMICAL NEWS of November 27th; but it occurred to me that an arrangement similar to that used to show waves in water would probably serve the purpose. I therefore tried the following plan, which, though not so successful as the one I shall afterwards describe, is well worth trying:-A box with a glass bottom was filled with water and a lime light placed underneath the box. On throwing a spot of liquid, giving a cohesion figure, on to the water, the figure, more or less definite, was exhibited on a tracing paper screen placed above the box. with a candle underneath the box the figures were visible, but of course not sharp as when the oxy-hydrogen light was used. This experiment led me to devise the following arrangement, which, with such liquids as I have tried, serves admirably, the figures being projected on to the screen with great clearness :

Even

An

In the first place several troughs are made to hold the water on which to place the creosote, &c. Those I have are made of plate glass. A piece of glass 5 inches square and inch thick has a hole 3 inches diameter cut in it, and this, when laid on a plain piece of glass, forms a circular trough, 3 inches diameter and inch deep. ordinary oxy-hydrogen lantern, from which the nozzle has been removed, is now tilted back so that the light from the lantern is thrown perpendicularly upward, and the trough placed just over the front of the lantern as though it were a lantern slide. The nozzle of the lantern, fitted to a projecting arm, is then brought over the trough and an image of the upper surface of the water obtained on the ceiling. On now placing a drop of creosote on the

A

Graphite

Troïlite Schreibersite

I will remark upon this subject that those numbers are exact exclusively for the analysed specimen. In other parts of the same mass, crust, stony matters, &c. may be found, and perhaps some of the above-named principles can disappear.

I will show in another paper how my studies have given me a good rule for the classification of meteoric irons. Paris, November 27th, 1868.

water an image of it is seen on the ceiling. If it be desired to throw the image on to a vertical screen, a reflecting prism is placed on the nozzle, by which the desired effect is obtained.

referring to the accompanying figure, in which A is the The arrangement will be completely understood by lantern turned back; c, the chimney; B, the glass trough to hold the water on which the creosote or other liquid is

CORRESPONDENCE.

ON THE FUMING OF CERTAIN ACIDS.

To the Editor of the Chemical News. SIR, I was struck by the inquiry of a student in a late number of the CHEMICAL NEWS, why hydrochloric acid fumes when let out into the air, while ammonia, which has a much stronger attraction for water, does not?

If the student continues to read his chemistry with the same inquiring spirit that prompted this question, he will not only become a good observer himself, but he will have an influence in making our text-books better exponents of observation than some of them are, in many respects, at present.

It is not an unusual fault that our books contain too many bald facts often adopted without sufficient verification, and too little reasoning. Facts are good soldiers; theory a good general; but unless they work together, there is very little real fighting.

But to the point. Why does not ammoniacal gas

fume when let out into the air?

I took the specific gravity of a solution of ammonia and found it to be 0.889. Twenty-four drachms of this were put into a flask and heated over a spirit lamp. It at once entered into brisk ebullition, and there was a great head of gas bubbles from which very large bubbles expanded and burst. The thermometer rose slowly to 100° F. When the lamp was removed the boiling ceased instantly, but two or three rapid streams of small gas bubbles continued to be discharged for some time from black specks in the glass, which acted as nuclei. When the temperature was at 160° the lamp was removed, and the solution left to cool. It still smelt of ammonia; the lamp was replaced, and no gas bubbles were given off until the temperature had again risen to about 160°. The appearance of ebullition was much less marked than before, and the temperature rose to 208°, at which it became stationary (Barometer, 28.69 inches). When cold, only 10 drachms remained of the 24. The specific gravity was now 0.997. The liquid had a faint smell of ammonia and a slight action on turmeric paper; but on putting the glass into another room, where the liquid could not re-absorb ammonia, it lost, in the course of some hours, all smell; it had no action on turmeric paper; it was, in fact, brought back to pure water.

If a similar experiment be made with a strong solution of hydrochloric acid, it will be found impossible to boil away all or nearly all, the acid gas. If we operate on the acid solution of specific gravity 121, it will part with gas until it has a density of 110 (at 60°), when it will have a boiling point at 233° F., and will distil unchanged.

We see, then, that although ammoniacal gas and hydrochloric acid gas are greedily absorbed by water, there must be some important differences in the constitution of the respective solutions. We have seen that the alkaline solution is much lighter than its own bulk of water, the acid solution much heavier; that the presence of ammonniacal gas in water lowers its boiling point, while the presence of hydrochloric acid in water has a contrary effect. Hence the mode of combination between ammonia and water must be different from that between hydrochloric acid and water. The one must be a case of simple adhesion, the other of true chemical combination as well as adhesion.

Ammonia let out into moist air, simply adheres to the moisture and increases its volume. Vapour of alcohol, ether, &c., does the same. Now any amount of aqueous vapour that the air can maintain in an invisible elastic state, at a given temperature, it can maintain with increased effect in the case of ammonia vapour, alcohol vapour, &c. Hence the combination of these vapours with the moisture of the air is necessarily an invisible compound.

Hydrochloric acid gas, on the other hand, let out into the air, combines chemically with the moisture, producing condensation or diminution of bulk. Hence the compound is visible just as the condensation of pure steam in air produces visible vapour.

Fuming nitric acid and Nordhausen sulphuric acid are also cases in point. Concentrated nitric acid exposed to the air absorbs moisture until it attains the density of 1424, when it distils unaltered at a boiling point of 250°.-I am, &c., C. TOMLINSON.

Highgate, N., Dec. 28, 1868.

MISCELLANEOUS.

Sale of Poisons Act.-A very important act of Parliament-the Amended Pharmacy Act, or Sale of Poisons is directed that on and after the 1st day of January, 1869, Bill-came into operation on the 1st inst. By this act it registered according to the acts now in force as pharmano poison shall be sold by any person except those ceutical chemists, or chemists and druggists; and that every box, bottle, vessel, or wrapper containing poison shall be distinctly labelled with the name of the article, together with the name and address of the person selling the same. All those in section A are strictly forbidden to be sold to A schedule of poisons is given, divided into two sections. any person not known to the seller, unless introduced by some person known to the seller; a register of the sale is compulsory, and must be attested by the signature of the purchaser and his or her witness; while those poisons included in section B need only to be properly labelled. All medicines must be compounded with articles prepared strictly according to the British Pharmacopaia; and every adulteration of any article retailed shall be deemed an admixture injurious to health, punishable under the provisions of the Act for Preventing the Adulteration of Articles of Food or Drink. The poisons defined by this act are in Part 1, arsenic and its preparations, prussic acid, cyanides of potassium and all metallic cyanides, strychnine and all poisonous vegetable alkaloids and their salts, aconite and its preparations, emetic tartar, corrosive sublimate, cantharides, savin and its oil, ergot of rye and its preparations; and in Part 2, oxalic acid, chloroform, belladonna and its preparations, essential oil of almonds, unless deprived of its prussic acid, opium, and all preparations containing opium or poppies. Among the preparations which, according to this act, will have to be labelled as a poison, we notice paregoric elixir, child's cordial, syrup of poppies, and every other syrup, tincture, or lozenge which shall contain the smallest portion of opium or morphia. The object of this Bill is evidently to prevent ignorant persons from dealing in articles the composition of which they do not understand. It will also serve as a check to the poisoning of children by the administration of such preparations as child's cordial, soothing syrups, &c. The fine for selling these articles without being properly labelled is heavy, as it is also for selling them without being properly licensed.

The Gas Supply of the City.—In the month of July of last year an important act of Parliament was passed for improving the quality of the gas supplied to the City of London by the several City Gas Companies, and also to those parts of the Metropolis supplied by the Chartered Gas Company, whereby the quality of the gas was raised from a standard of twelve candles to fourteen, without increase of charge to the consumer; and with the view of securing the provisions of the act, and enforcing penalties in all cases of default, a chief gas examiner is appointed by the Board of Trade to receive the reports of the daily testings of the gas and to decide all matters of dispute respecting the quality of the gas. It is also the duty of the chief gas examiner to report to the corporation, to the

Metropolitan Board of Works, and to the several companies the quality of the gas supplied during the quarter; and in this capacity, and in accordance with the provisions of the 71st section of the City of London Gas Act, 1868, Dr. Letheby has recently submitted his report to the Corporation of London, from which it appears that since the act came into operation, on the 1st of October last, the gas of the several companies supplying the city has been tested every night at intervals of not less than an hour between the hours of five o'clock and ten o'clock. The results are as follows:

Illuminating Power in Standard Sperm Candles. Maximum. Minimum. Average City of London Gas Light, and Coke Co. 16:30 13'99 15'13 The Chartered Gas Light, and Coke Co. 16*36 14.13 15'26 The Great Central Gas Consumers Co. 16'64 13'46 14'90 It appears, therefore, that the illuminating power of the gas has ranged from 13:46 candles to 16.64-the average for the quarter being 15 13 candles for the City Company, 15.26 for the Chartered, and 14'90 for the Great Central. The daily returns show that on three occasions only the gas has been below the standard, and these were no doubt due to causes which admit of satisfactory explanation. With regard to the purity of the gas, he reports that the gas of the Chartered and Great Central Companies have always exhibited traces of ammonia, but that the gas of all the companies has been constantly free from sulphuretted hydrogen. The amount of sulphur present in the gas has ranged from 7'9 grains to 26.52 per 100 cubic feet, the proportion of this impurity being as follows:

Grains of Sulphur per 100 Cubic Feet of Gas.

Maximum. Minimum. Average. 10'64 16.89

City of London Gas Light, and Coke Co. 22:28 The Chartered Gas Light, and Coke Co. 26'52 The Great Central Gas Consumers Co. 24.94

The smallest amount of sulphur has been in the gas of the Great Central Company, and this is attributed by Dr. Letheby to the excellent system of purification adopted by that company. The proportions of sulphur have been determined by the instrument known as Dr. Letheby's sulphur test, which is that recommended for use by the gas referees appointed under the act. It is extremely desirable that this impurity should be reduced to the smallest quantity, on account of the corrosive action of the products of its combustion.

CONTEMPORARY SCIENTIFIC PRESS.

(Under this heading it is intended to give the titles of all the chemical papers which are published in the principal scientific periodicals of the Continent. Articles which are merely reprints or abstracts of papers already noticed will be omitted. Abstracts of the more important papers here announced will appear in future numbers of the "Chemical News.")

Comptes Rendus.

October 5, 1868.

CHEVREUL," Researches on Experimental Methods in Chemistry." CROULLEBOIS, "On the Dispersive Power of Gases and Vapours." DUMAS, "Note on Drechsel's Method of Preparing Oxalic Acid from Carbonic Acid." M. BOUCHERIE, "Note on the Preservation of Wood." A. HOUZEAU, "On Testing Campeachy Wood and other Dye Stuffs." N. ZININ," Contributions to the Knowledge of the Stilbene Series." HIORTDAHL, "On the Native Alloys of Gold and Silver from the Kongsberg Mine, Norway." A. GAUTIER, "On Isopropylcarbylamine and Isopropylamine." J. NEY, "A New Galvanic Battery.

October 12, 1868.

Bulletin de l'Académie Imperiale des Sciences de St. Petersbourg. June 4, 1868.

P. KOSTYTSCHEF and O. MARGGRAF "On the Chemical Composition of the Fossil Sponges of the Apatites of the Cretaceous Beds of Russia." N. ZININ," Note on Chloro-benzil." DUKE NICHOLAS VON LEUCHTENBERG, "Note on Kotchoubeite, Kämmererite, and Pennine." H. JACOBI, "On the Electro-Deposition of Iron." KLEIN, On the same subject. O. STRUNE, "On the Spectrum of the Aurora Borealis." A. FAMINTZIN, "On the Action of Light on Cell-division in Spirogyra."

Annales de Chimie et de Physique. September, 1868.

P. AUDOUIN, "On the Use of Liquid Hydrocarbons for obtaining High Temberatures and for Heating Steam Boilers. A. RENARD, “On the Volumetric Estimation of Zinc." E. BOURGOIN, "On the Part taken by Water in Electrolysis." A. MARTIN, "An Improved Process for Silvering Glass by means of Inverted Sugar." P. SCHUTZENBERGER, "On some Reactions producing Oxychloride of Carbon, and on a New Volatile Platinum Compound." DE LAPPARENT, "Report on Pasteur's Method of Preserving Wine by means of Heat." P. SCHUTZENBerger, "Memoir on the Colouring Matters extracted from Persian Berries."

Bulletin de la Société Industrielle de Mulhouse.

July, 1868. Supplement.

J. KOLB, "Memoir on Bleaching Fabrics." H. KECHLIN, ́" On some Mordants, other than Alumina and Iron, for Garancine Colours, with especial reference to a new Red (grenat) Dye obtained with Chromium." A. SCHEURER-KESTNER and C. MEUNIER, "Researches on the Combustion of Coal." C. KECHLIN, "A Process for Extracting the Colouring Matter from Waste Fabrics Dyed with Garancine." M. PARAF-JAVAL, "Note on a Method of Preventing the Injurious Action of Aniline Black on the Copper of Printing Rollers." SCHNEIDER, On the same subject. MARNAS," A New Aniline Dye."

Mr. Bassett's communication "On a Mercury Compound of Acetylene," together with those of several other correspondents, are unavoidably postponed till next week.

Querist. One part of sulphur will dissolve in about 2000 parts of glycerine, and we believe the solution has been proposed as a local application in some affections of the skin.

Oriens asks "whether there is, in the service of the Siamese Government, any opening for a technological chemist experienced in the analysis of soils, ores, furnace products, and drysalteries, and if so, what would be the channel for an applicant to offer his services?" Perhaps some of our correspondents may be able to answer this inquiry.

Communications have been received from W. T. Suffolk; H. Sanders; G. Marrison; J. Dicker; W. Salter; Dr. Letheby'; O. Richter; J. Wilson; E. Kopp; L. Cookson (with enclosure); J. Pride (with enclosure); S. R. Muspratt; T. Vosper; A. N. Tate; T. Watts; J. Parnell; Dr. R. Angus Smith; Rivington and Co.; W. Macnamara; J. A. Brand; D. Forbes, F.R.S.; G. Young (with enclosure); D. W. Ladley; J. W. Sugg; and C. K. Jewett, Göttingen (with enclosure).