CORRESPONDENCE.

Explosions in Veins of Lead Ore.

To the Editor of the CHEMICAL NEWS. SIR,-I have often heard it stated that even the polished sides (slicken sides) of the veins of lead ore in Derbyshire limestone will explode more or less violently when they are scratched or struck with a hammer. In the lead districts I have recently visited in Germany, where the ore traverses greenstone and schists, as well as limestone and barytine, I could obtain no account of such explosions. Sir Charles Lyell says of the Derbyshire veins: "When one side of the vein stuff is removed, the other side cracks, especially if small holes be made in it, and fragments fly off with loud explosions, and continue to do so for some days. ... These phenomena and their causes (probably connected with electrical action) seem scarcely to have attracted the notice which they deserve." Can any of your numerous readers supply the results of their observations on this point, or suggest any theory of these remarkable explosions? I am, &c.,

44, The Cedars, Putney, October 16.

T. L. PHIPSON, Ph.D.

Baron Seguier's Experiment on the Incompressibility of

Water.

To the Editor of the CHEMICAL NEWS. SIR,-Some short time back, Baron Seguier demonstrated the incompressibility of water by taking a glass cylinder and plunging it into water, and letting a leaden ball drop within it. I have found that a sphere does not succeed so well as an elongated spheroid, or a cylinder of brass or any other metal, with one end filed to a point, and the cylinder allowed to fall with the point first. This experiment, of course, is only a modification of Professor Faraday's, performed at the Royal Institution some few years back. In the memoirs of the Royal Academy of Sciences of Paris, tome 10th, anno 1693, page 397, will be found a theory advanced by M. De la Hire, accounting for the resistance of air and water to sudden motion, which, I think, satisfactorily accounts for the above experiments. He observes "that the resistance to motion is by so much the greater as the motion is the more sudden; and when it is so to such a degree that what resists has not the time to recede, then a body, very weak of itself, may supply the place of one that is immoveable, and of an invincible obstacle. It is for this reason that air and water, struck with such velocity, and with so sudden a blow that they have not time to recede, become fixed points,-the one for the flight of birds, the other for the action of oars." This theory is at once both conclusive and reasonable, and the experiments of Faraday and Seguier only serve to prove the verity of De la Hire's theory; and, therefore, the modern theory accounting for their experiments is superfluous, and, of course, unnecessary; for when the surface of water is suddenly struck, the point of contact is, for the time being, an immoveable fixed point; and when the water is enclosed in a glass cylinder, the body with which the water is struck is retained for a conceivable space of time on the surface of the water; the water then gradually rises between the sides of the striking body, which allows the body to sink; but if the body strikes with much greater force than will allow the water to have time to rise, the water seeks another direction, and consequently splits the glass. Should the body be an elongated sphere, or a cylinder with the lower end pointed, then the force required to split the glass tube is not so great, for the tapering end, acting as a wedge, passes or penetrates the water much quicker than a sphere would. Of course, the length of the wedge bears a relation to the force exerted.

Should you favour me with an insertion of this letter, I shall feel greatly obliged, and perhaps it might prove interesting to a few, at least, of your readers. I am, &c. JEREMIAS.

MISCELLANEOUS.

Royal Polytechnic Institution.—Some recent changes have been made in the entertainments at this Institution which deserve notice. Professor Pepper has introduced a lecture on polarised light and the phenomena of diffraction, in the course of which he gives a very clear exposition of the theory of light and the phenomena in question, and we need hardly say exhibits some most beautiful experiments. Mr. King describes the thermo-electric battery, illustrating his description by experiments with a large pile on Marcus' principle. Some new ghost scenes have been introduced, and this part of the evening's amusement has been made more attractive than ever. There is plenty of other entertainment provided for those who, without being necessarily "dull fools," are yet unable to see "how charming is divine philosophy." The excellence of Mr. Pepper's lecture on light induces us to ask whether it would not be possible to give a higher educational value to the lectures at the Polytechnic by the delivery of short courses on chemistry and different branches of natural philosophy, similar, we may say, to the Christmas juvenile lectures at the Royal Institution. Illustrated as the lectures always are at the Polytechnic, each one would be entertaining to the occasional visitor, while giving to the regular attendant some real knowledge of science. We throw out this suggestion for Professor Pepper's consideration when he is thinking over his holiday programme.

=

Results of the Explosion of Nitroglycerine.— The new blasting material is a light-yellow oily fluid-a compound of glycerine and nitric acid, its chemical formula being CH,O,(NO3)3, which gives 18 parts of oxygen; and Mr. Nobel claims that as by combustion the carbon takes 12 atoms of oxygen, and the hydrogen 5, its complete combustion leaves a surplus of O, only. He states, moreover, that each 100 parts of exploded blastingoil leaves a residue of-carbonic acid, 58; water, 20; oxygen 3; and nitrogen, 18 = 100; and that as the specific weight of the oil is 16, one volume produces nearly 1300 volumes of gas-that is to say, steam, 554; carbonic acid, 469; oxygen, 39; and nitrogen, 236 1298 volumes. Weight for weight, the blasting-oil bears very favourable comparison with gunpowder, which is calculated to produce ordinarily about 250 volumes of cold gas only; the nitro-glycerine would, consequently, appear to be, other things being equal, about five times as effective as gunpowder. But Mr. Nobel goes further than this, for he remarks that it is difficult to determine the degree of heat produced by an exploding substance, and that, according to theory, the blasting-oil, on account of its complete combustion, ought to develope a more intense heat than gunpowder, and this appears to be borne out by experiment; whence he assumes that the heat developed by the explosion of nitro-glycerine is twice that generated by gunpowder, and from this calculates that nitro-glycerine, compared with gunpowder, possesses about 13 times its power, when volumes are considered, and 8 times its power for equal weight; and that owing to its rapidity of explosion its advantages are still greater.

Sale of Capsuled Articles.—At the meeting which we announced, and which took place at the house of the Pharmaceutical Society, Bloomsbury Square, on October 5, the following resolutions were moved and carried:-1. "That the Patent laws, as illustrated by recent Chancery suits respecting capsuled articles, are injurious to trade in general, and especially embarrass international and retail trade, and should be amended." 2. "That a petition embodying the foregoing resolution, and detailing the proceedings referred to, and also praying the amendment of the Patent laws, be prepared and presented to Parliament." These resolutions, it must be admitted, go to the root of the matter; but the remedy which they suggest for present grievances will probably be withheld for many a year.

We believe that when the question is tried the retailer will be held blameless, a belief which is greatly strengthened by the speech of Mr. Flux (the solicitor) at the meeting. We extract some portions of this address from the report of our contemporary, The Chemist and Druggist: Mr. Flux (solicitor to the Pharmaceutical Society) said that as Mr. Hills had asked him whether the suits which Mr. Betts had commenced were to be tried, he thought it only right to say that a great many gentlemen had done as Mr. D'Aubney had done. They had taken eminent advice, and acting on it they had compromised their suits, probably paying handsome sums and costs, thereby affording encouragement to Mr. Betts to pursue his system from one end of the country to the other. He could not with unbounded confidence say that these suits could be successfully defended, but he could say that he defended them with a fair amount of confidence as to the ultimate result. According to the reductio ad absurdum of the Patent laws, Mr. Betts might have a prima facie case in a court of equity, so that he might possibly succeed in getting a decree; but if he did, it would be, to the best of his (Mr. Flux's) belief, but a naked decree, without costs, against the defendant, who would perhaps have to pay his own costs, because any damages would be of such a ridiculously small amount. A Vice-Chancellor would probably say that Mr. Betts ought not to have gone to court systematically, as he had done, with such a large batch of bills; about twenty five, all struck off in blank as it were, the only change being the substitution of one gentleman's name for another. So much for Mr. Betts's form of proceeding. But now, looking at the whole matter, he should be able to prove that which perhaps was unknown to other professional gentlemen who had advised on this matter. Mr. Betts had not a patent for capsules, but for metal of which capsules could be made. He should be able to prove conclusively that Mr. Betts had not only sold large quantities of his metal, but millions of capsules made of his metal, without any distinguishing mark being put upon them; and it was within his own knowledge that Mr. Betts's own agent could not tell, when a capsule was placed in his hands, whether they were made by him or not. Mr. Betts's confidential agent was one day in his (Mr. Flux's) office; and by way of parenthesis he might say that he then believed that they had come to an amicable termination of the matter, and that it would have been a drawn battle and peace would have been established; but it was impossible to say in ernnection with these matters when they had arrived at a conclusion, and he now believed they would have to fight to the end. On the occasion referred to, they discussed the possibility of distinguishing between a genuine and what was not a genuine article. He (Mr. Flux) had had supplied to him, and with the means of proving it, Betts's plate and his capsules. He placed them in Mr. Campbell's hands, and said to him. "Tell me, are they Mr. Betts's manufacture or not?" Mr. Campbell turned them over and over again, and said, "If I had a microscope, perhaps I could tell." (Laughter.) He then said to him, "Then if that be the case, tell me how an outsider can say that these are Betts's capsules or not." (Hear, hear.) To which he replied, Perhaps they cannot tell." (Laughter.) He repeated his question, "Tell me, without a microscope, are they Betts's manufacture or not?" and he replied, "They are not." (Hear, hear.) Upon which he (Mr. Flux) said, "Then I can prove most distinctly that they are." ("Hear, hear," and laughter.) Now, in the course of such a proceeding as that, and in the face of his having sown broadcast over this and foreign countries capsules of his manufacture without the slightest distinguishing mark, occurred to him (Mr. Flux), that to prove that the capsules proceeded upon were an infringement of the patent would be a very difficult thing for Mr. Betts to do; and at any rate it would be capable for the defendants to show that in selling these capsuled articles they acted in

66

perfect innocence, and that they were in a trap which Mr. Betts himself had laid for all the world-he did not mean to say openly and purposely—but which, nevertheless, was in effect a trap into which the retailers had fallen. In the face of that, and according to the law of justice which he had ever seen administered in the Court of Chancery, he could not see how the defendants could be cast in costs, and he had a strong conviction that Mr. Betts would have to pay them. So much, then, for the matter that had been referred to him by Mr. Hill's question; and he would say a few words with reference to the proposition before the meeting. Mr. Betts's patent was not, as he had before said, for capsules, but for the metal of which they were made. In the ordinary retail trade he did not think they could take up an article in any one of their shops that might not, for what they knew, expose them to a Chancery suit in half a dozen different directions. The capsule on the top of the bottle might expose them to a suit in Chancery, not because of its being a capsule, but because it was made of a given metal. The pot, the label, even the paper, and the colour of the ink might be covered by patent or registered designs, and render them liable to as many Chancery suits; and really if such suits as these could prevail, they could not conduct the ordinary retail trade of the country with any amount of safety. Now, with regard to the international part of the question. Take, for instance, Vichy water. By the law of France, he believed, Vichy water must be capsuled.-Mr. Hills said it was now covered with tin. They had given up the use of the composition.— Mr. Flux: By the law of France Vichy water must be capsuled, but if by the law of England it could not be imported with capsules-without capsules it would be contraband leaving France, with capsules it would be contraband touching the shores of England. There were many articles which were imported from France that were never opened until they got into the consumer's hands, which might be full of explosive matter in the way of Chancery suits. Now, let them look at the question as it affected the trade in various portions of Great Britain, Betts's patent did not extend to Scotland. Messrs. Tennant, of Scotland, manufactured bottled beer, which they fastened down with metallic capsules, and sent direct from Scotland to India they did not infringe the patent by the use of the capsules; they, however, received an order, the other day, for some beer to be sent to a foreign port, and as there was no steamer direct from Glasgow to that port, the beer was sent to Liverpool for transhipment to its destination. Now, by its arrival in the port of Liverpool, although it was never intended to be consumed within the realm, it was contraband. A Chancery suit had been commenced, and no doubt the injunction would be granted; and that being the case, it appeared to him that the resolution was fully supported, and that the patent laws interfered with international trade, and materially embarrassed the retail trade.

ANSWERS TO CORRESPONDENTS.

TO OUR READERS.

Dr. Odling's lectures, now nearly completed, will be followed immediately by the Cantor lectures delivered by Mr. T. C. Calvert, F.R.S., "On Recent Improvements in Chemistry as Applied to the Arts,"

irritant.

Subscriber.-Answers according to Fownes and Gregory will be accepted. The next edition of Fownes, which will be issued shortly, will have formula on the new and old systems, side by side; if yet another edition of the book should be called for, it has been decided to reconstruct the book on the new system. The second question we are unable to answer, not having this year's regulations at hand.

Examination of Insoluble Substances for Alka. Hes. The ordinary process of fusion with baryta for the detection of alkalies is attended with some inconvenience. The baryta itself is not a pleasant reagent, and it is not always easy to obtain it free from alkalies. If the fusion be performed in platinum, the metal is slightly attacked; if in porcelain, there is danger of introducing alkali from the glaze, which is always affected. The fused mass is generally difficult to detach, and is so slowly attacked by water that it has to be dissolved in hydrochloric acid, which involves the separation of a large quantity of baryta, as well as of magnesia, before seeking for the alkalies. I have found that the use of a mixture of nitrate of baryta and sulphur obviates these difficulties, and enables the decomposition to be easily effected by the heat of a spirit-lamp.

Nitrate of baryta is, of course, easily obtained in a pure state, and flowers of sulphur may be depended upon

as free from alkalies.

One part, by weight, of the substance under examination is mixed with one part of flowers of sulphur and six parts of nitrate of baryta; the mixture is introduced into a porcelain crucible, and quickly heated over a spirit-lamp or air-gas flame, until the deflagration is over; about one minute suffices for this. The crucible is allowed to cool, the fused mass loosened at the edge with the point of a knife, and thrown into a mortar, where it is easily reduced to a fine powder. (The glaze of the crucible will be found quite untouched.) The powder is thrown into a little boiling water, in a dish, boiled for a minute or two, and filtered. The filtrate is mixed with ammonia and carbonate of ammonia, and boiled, to separate baryta and other alkaline earths which may be present, and after these have been filtered off, the solution is evaporated, and the examination for alkalies conducted in the ordinary manner.

Flint-glass (5 grains) was examined in this way. The potassium was very readily detected. No potassium was found to have been left in that portion of the fused mass which was insoluble in water.

Felspar (5 grains) gave an equally satisfactory result. In this case, also, no potassium could be found in the residue left by water.

Window-glass (5 grains) gave the sodium precipitate very distinctly with antimoniate of potash, in characteristic strongly-adherent crystals. No potassium was

detected.

Cryalite (5 grains) also gave antimoniate of soda very distinctly. No indication of potassium.

The economy of time, fuel, and crucibles, resulting from the application of the processes above described, will be found, I hope, to justify my belief that they are not undeserving of the attention of a society which includes a large number of practical chemists.-Journal of the Chemical Society, September, 1865.

Process for the Extraction of Lithium, Casium, Rubidium, and Thallium from Lepidolite,* by M. A. SCHRITTER.

THE author's process, which may be used on a large

Journal für Praktische Chemie, xcil., 275.

VOL. XII, No. 308-OCTOBER 27, 1865.

scale, consists in, first, simply fusing lepidolite at red heat; it expands greatly in fusing, so that the mass must be frequently stirred; when sufficiently fused pour it into cold water, and pulverise and wash the vitrified mass thus obtained. (The lixivium will contain small quantities of alkaline metals, which will serve for the treatment of another portion.) Treat the washed mass by hydrochloric acid (1 part of lepidolite requiring 2 parts of hydrochloric acid at 110 of density). After several hours' boiling, separate the greater part of the silica, and having added nitric acid and peroxide of iron, precipitate by carbonate of soda, so as to diminish the iron, alumina, lime, magnesia, and manganese; the liquid should be so diluted that lithia, the carbonate of which is very little soluble, should not be precipitated. The liquid will then contain only the chlorides of the alkaline metals and a little silica. By evaporating in an iron vessel a little more carbonate of magnesia is separated; then saturate with hydrochloric acid, and add a watery solution of chloroplatinate of potassium, sufficient in quantity to precipitate all the rubidium, caesium, and thallium. (The quantity to be added should be determined by a previous assay.) filtered liquid, containing the excess of platinum and lithia, precipitate by sulphuretted hydrogen to separate the platinum, then concentrate and treat it by carbonate of soda; in this way the lithia is precipitated in the state of carbonate.

The

The advantage of this method consists in the direct fusion of the mineral, and may be applied to all lithion micas. 1000 parts of lepidolite treated in this way will give 78 parts of carbonate of lithia, 6.5 parts of chloride of casium and rubidium, and o·6 of thallium, supposing the operation to be continuous.

by the action of gaseous phosphoretted hydrogen on iodide of cyanogen. The principal reaction is complicated by secondary reactions, which I have studied for some time.

In the course of these researches I have noticed the production of a compound perfectly free from phosphorus, very little soluble in ether, and which made me suppose the existence of a combination of hydrocyanic and hydriodic acids, formed in the preceding reaction; it is this, in fact, which confirms the direct experiment.

I obtained this combination by causing to arrive simultaneously in a large balloon a current of dry hydrocyanic acid, and one of dry hydriodic acid; the two gases combined immediately at the ordinary temperature into a white amorphous body, precipitated against the sides of the receiver.

In other operations I passed as cous hydriodic acid into anhydrous hydrocyanic acid, surrounded with ice. The liquid soon solidified into a nearly white mass. The two bodies combine as easily as ammonia and hy driodic acid.

Washing the compound with ether takes from it the excess of hydriodic and hydrocy anic acid, as well as a little free iodine; it is then nearly pure, and may be crystallised in absolute alcohol.

It is a solid body, in white crystals belonging apparently to the rhomboidal system, odourless, and with a fresh, saltish taste, becoming slightly bitter, but not in ↑ Bulletin de la Société Chemique, p. 88. 65.

196

CHEMICAL NEWS, Oct. 27,

the least acid; in water and alcohol it dissolves readily, and but very little in ether; it does not seem to attract much atmospheric moisture.

It is infusible, but may be sublimed in dry air without undergoing much decomposition; a small quantity of iodine is set at liberty, with no deposit of carbon; volatilisation seems to take place towards 350 or 400°; but it commences at 180°. Submitted for some time to 150° it becomes greyish and earthy. Exposure to the sun does not alter it.

The analyses hitherto made authorise me to attribute to this body the composition NH,I, and from its properties it seems to be an iodide of ammonium, in which the triatomic radical CH holds the place of H3. I will, then, represent this body by the formula

N

{

CH"

H I

TECHNICAL CHEMISTRY.

The Allotropic Conditions of Iron and their Part in Metallurgy," by M. DE CIZANCourt. OXIDES of iron have long been considered as the degrees of oxidation of one metal, which was supposed always to present itself when in a metallic state, with absolutely identical characteristics, if of the same degree of chemical purity or of the same composition. This supposition has given rise to the metallurgic theory still generally admitted. All the differences found in the products of iron are consequently attributed exclusively to differences in the chemical composition. These products are now classed in three groups; cast iron, steel, and wrought iron, merely according to the amount of carbon they usually contain. However, certain cast-irons identical in composition, are so different in appearance and tically it is absolutely necessary to distinguish them ; on the other hand, there are certain cast-irons of the same

In this combination all the properties of cyanogen or hydrocyanic acid are entirely lost. The aqueous solution is neutral, or almost so, to papers, but gradually acidifies. Powdered, moistened with a very little water, and heated for some time, it gives crystals of iodide of ammonium, and disengages formic acid, which is deposited in minute liquid drops on the sides of the tube.

It is, however, impossible to find any trace of hydrocyanic acid in the aqueous solution.

The action of the water, then, is thus expressed

Treated by diluted potash this compound immediately disengages all its nitrogen in the form of ammonia; iodide and formiate of potassium are produced, but no trace of cyanide.

Nitrate of silver also precipitates all the iodine. The iodide is mixed with a white compound soluble in excess of water.

Bichloride of platinum is partially reduced, at the same time that a yellowish crystalline body is formed, which has not yet been analysed.

Hydrobromic acid acts like hydriodic acid on hydrocyanic acid, this combination has not yet been studied; neither has the action of gaseous hydrochloric acid been investigated.

Like the compound above described, hydrocyanic acid, soluble organic cyanides, and metallic cyanides themselves, give, by the action of water and bases, ammonia and formic acid. But in these combinations the cyanogen disappears but gradually, and their solution long retains the characteristic properties of cyanides. It is thus only progressively, and by the prolonged action of water or of bases, that nitrogen and its compounds pass to the ammoniacal type.

composition as certain steels, and even steels which fact, in studying the metallurgic products of iron, the analysis can hardly distinguish from certain irons. In chemical composition is but a secondary consideration. isting between the properties of the various products, The really dominant characteristic is the relation exand the degrees of oxidation of the iron in the ores whence they have been extracted. The expression of this general and unvarying fact has, since M. Leplay's remarkable researches, become a kind of axiom, which may be thus rendered; steel ores produce only steel; or, from each ore its iron.

Berzelius has already classified the different combinations of iron by connecting them with two chemically distinct metals, to which he has given the names of "ferrosum" and "ferricum." It remained to ascertain whether these metals had a real physical existence, and could be found distinct in metallurgy. The discovery of the allotropic conditions served to decide the opinions on the property possessed by at least several bodies, even while presenting the same composition when analysed, of appearing in very different conditions with peculiar characteristics, which they may preserve, even when undergoing certain transformations or combinations.

The facts I am about to disclose show that iron in a metallic form possesses at least two allotropic conditions analogous to those of sulphur and phosphorus. The two principal conditions correspond to those described by Berzelius.

Ferrosum is the metal contained in the ores of protoxide.

Chemical Society. The next meeting of this Society will take place on Thursday evening next, at 8 o'clock, when Professor Church will read a paper "On some New Cornish Minerals."

Ferrosum, in the state of white cast-iron, may be obtained with so much the more facility, that the reduction of the ore takes place at a lower temperature, and that the product cools more rapidly. This is, then, the condition corresponding to the lowest temperatures—that,

* Comptes Rendus, lxi., 578.