252

the cobalt, nickel, and zinc, whilst the undissolved portion contains all the alumina and chrome with the residue of the nickel, cobalt, and zinc. The analysis is completed by known methods. If iron and manganese alone have to be separated from alumina and chrome the process is complete and precise.

New Formation of Glycocoll by means of Nitroacetic Ether.-M. de Forcrand. Nitro-acetic ether yields glycoco!l on reduction with tin and hydrochloric acid.

No. 20, May 19, 1879.

A New Derivative of Nicotin.-A. Cahours and A. Etard. The new base, to which the authors assigned the name thio-tetra-pyridin, has a composition represented by C40H18N4S2.

Transparence of the Media of the Eye for the Ultra-violet Rays.-J. L. Soret.-The author concludes that the absorption of the totality of the media of the eye must render it impossible to perceive rays whose refrangibility exceeds that of the extreme radiations of the solar spectrum, say the ray U.

Preliminary Researches on the Action of Acids upon Salts without the Intervention of a Solvent. M. Lorin. The direction of the results indicates chemical action more or less distinct, and which, for the fatty acids, decreases from formic acid to each of its successive homologues.

Presence of Mercury in the Mineral Waters of St. Nectaire.-E. Willm.-The author's results have been mutually contradictory. Supposing mercury to be a constant element of the water the quantity shown by his only affirmative experiment falls far short of that resulting from the analysis by Dr. Garrigon.

The Mode of Combination of Iron in Hæmatoglobin.-L. Jolly.- The author concludes from his analyses that iron occurs in the blood-globules merely as phosphate.

Bulletin de la Société d'Encouragement pour l'Industrie Nationale.

No. 64, April, 1879.

Report presented by M. Ed. Collignon on the Electric Brake of M. A. Achard.-The moment that an electric circuit is broken, whether by the separation of a part of the train, by carriages getting off the line, or by fire, the wheels are automatically locked.

Report by M. Sebert on the Electric Bells of M. Laville. The arrangement of this apparatus cannot be made intelligible without the aid of the accompanying illustration.

Revue Universelle des Mines, de la Metallurgie, &c., Tome 4, No. 3, November and December, 1878. Explosions Caused by Dust.-This paper recounts the facts laid before the Société d'Encouragement by Prof. Lawrence Smith in November, 1878, and the discussion on the same subject at the Academy of Sciences.

No. 1, January and February, 1879.

Relation between the Temperature of the Earth and the Depth below the Surface.-P. Van Dijk.The author draws the following conclusions:-1 he increase of the geothermic scale proves that the earth is engaged in a continual process of cooling. This increase corresponds to the law of the refrigeration of a spherical body, having a uniform elevated initial temperature. The degree of cooling differs much for different parts of the earth's surface, according to their geographical and thermological position, and exercises an important influence on

{CHEMICAL NEWS,

June 6, 1879.

the vertical distribution of underground heat in any place. The loss of heat which the earth incessantly undergoes, from its surface being infinitely small, compared with the quantity stored up within, a large part of the earth's interior must still possess a very high temperature. The real geothermic progression, as accessible to human observation, far from indicating a minimum thickness for the earth's crust, imposes, on the contrary, a very narrow limit on the maximum temperature of the earth's interior. By the abstract application of this progression we should be led to ascribe to the earth's centre a heat not exceeding 100°. Actual facts observed, however, cannot be more simply explained than by the reaction of an igneous or fused nucleus, of a crust of considerable thickness, and having little conductibility for heat. The thickness of the earth's crust is very unequal, probably three times greater in the polar regions than in the volcanic regions of the Equator, and in one and the same latitude greater beneath the sea than on dry land. The greatest differences of thickness for one and the same latitude are met with in countries where, with an elevated mean temperature at the surface, the alternation of dry land and deep sea is most frequent. The volcanic character of the Eastern Archipelago agrees with this conclusion. According where the terrestrial crust is thinnest a temperature of 3000° will be found at the depth of 21 geographical leagues, not more than 1-40th of the earth's radius. In the polar regions it is probably more than four times as thick.

Biedermann's Central-blatt. Heft 3. March, 1879.

Pilter. The author proposes to obtain a cheap form cf Preparation of Artificial Animal Charcoal.-Th. gelatin by treating leather waste mixed with from 1 to 5 per cent of caustic soda with steam at a pressure of six atmospheres in closed iron vessels. The resulting semifluid mass is placed in a centrifugal, which keeps back the gelatin whilst tannate of soda runs off. So much of this jelly as is equal to 33 kilos. of dry glue is mixed with 50 kilos. bibasic phosphate of lime and 17 kilos. phosphate of magnesia. The mass is submitted to strong hydraulic pressure between layers of felt, dried at 110, and ignited in the ordinary manner.

Occurrence and Life of Bacteria and their Influence upon Yeast.- MM. Schnetzler, Bretefeld, Downes, Blunt, and Gunning.-Light is hostile to the development of bacteria and microscopic fungi. The exclusion of oxygen occasions the death of bacteria, but promotes putrefaction.

Reimann's Färber Zeitung,
No. 16, 1879.

Tartar Emetic in Dyeing.-The author points out that tartar emetic, as used in cotton-dyeing, serves not to fix the aniline colours themselves, but merely to fasten the tannin, thus playing the part of an indirect mordant. Several experiments have been instituted at the Färber Akademie in order to ascertain whether this application of antimony can be pronounced injurious to public health. It was found that water, in which cotton yarns dyed with aniline colours on a mordant of tannin and tartar emetic had been steeped, or especially boiled, gave distinct indications of antimony when tested in ordinary manners. The quantity of the metallic compound fixed on the fibre seems, indeed, far too trifling to have any effect upon human health. Still, in view of the panic which has seized upon the public mind, and of the tendency of the literary and political press to attribute all mysterious attacks of sickness to the influence of poisonous dyes, &c., Dr. Reimann-in our opinion very judiciously-advises dyers to dispense with the use of antimony, which will doubtless be found by no means necessary.

254

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PURE CHEMICALS, &c.,

was ignorant of Perkin's prior publications, and, believing Perkin in 1873, claimed priority.

THERE is a piece of recent chemical history which has already become much involved on account of the oversight of some writers, and as the threads happen to be in my hands, I think I shall do a good office to future students by laying these out straight at the present time.

In 1870 Mr. W. H. Perkin published in the Journal of the London Chemical Society a paper entitled "On Artificial Alizarin " (vol. viii., p. 143), in which at the end, in a footnote, the author says "When purifying artificial alizarin by converting it into an alumina lake, I found that upon digestion with carbonate of potash this lake gave a red-coloured solution containing a colouring matter, dyeing mordants very similarly to alizarin, with this difference, that the reds are more scarlet and the purples bluer or more slaty. I have not obtained this body in a perfectly pure state as yet, but it appears to be crystalline."

The investigation thus opened by Perkin was diligently prosecuted by him, and at the meeting of the London Chemical Society, held June 6, 1872, he read a paper on this body, an abstract of which paper is published in the CHEMICAL NEWS (vol. xxv., p. 284), and a fuller report of which appears in the Journal of the London Chemical Society, vol. xxv., p. 659, under the title "Note on a Secondary Colouring Matter Produced in the Preparation of Alizarin from Anthracen." In these publications he gives the formula of the new body as C14H8O5, and notes its relations and differences to and from the purpurin of madder. In the next volume of the Proceedings, or rather Journal of the Chemical Society, viz., vol. xxvi., 1873, Perkin published on page 425, under the title "On Anthrapurpurin," a long article on the same substance, to which were attached, as illustrations, pieces of cloth dyed with the substance as well as others dyed with alizarin. This article has been translated and quoted extensively in other publications, but the other articles seem to have been overlooked or forgotten. Hence have arisen some of the errors which I now propose to correct.

From the above references it will be seen that Perkin first separated out and recognised this new body in 1870, and diligently following up the research, published its formula in the beginning of June, 1872, and a full and exhaustive memoir in 1873.

In the Moniteur Scientifique for August, 1872, or just two years after the first publication by Perkin, and just two months after his second, in which he gave the formula of his new substance, appeared a communication announcing the discovery of a new product extracted from artificial alizarin by G. Auerbach, and named by him isopurpurin.

No mention whatever was made in this article of Perkin's prior publication, and it was of course generally inferred that Auerbach knew of them, but regarded his isopurpurin as a new discovery of his own, and not a mere confirmation of Perkin's work. In the course of time it appeared, however, that this was not the case, but that Auerbach

Into this error he seems to have led several writers. Thus, Graebe and Liebermann, in their report on Artificial Alizarin at the Vienna Exhibition, under the heading isopurpurin, refer first to Auerbach's publication_in_the Moniteur Scientifique of August, 1872, and then to Perkin's third publication in the Journal of the Chemical Society of 1873, omitting all reference to, and evidently not knowing of, his earlier publications in 1870 and June of 1872.

Rosenstiehl, in a recent article, has fallen into a like error, and credits Auerbach with first obtaining this body in an impure state, and Perkin with having first extracted it pure in 1873.

But admitting that Auerbach is right in assuming that what he extracted was only the anthrapurpurin of Perkin, it is evident that he has no claim whatever to priority, but that the substance must be credited to Perkin, and should be called by his name of Anthrapurpurin.

As a matter of fact, however, the substance actually extracted by the method described by Auerbach in 1872 is not anthrapurpurin, but a mixture consisting largely of a substance which was new at that time, but was afterwards isolated by Messrs. Schunck and Romer.

My reasons for this opinion are the following:-In the latter part of 1874 I had occasion, together with my friend Mr. Wm. E. Geyer, B.S., to repeat both Perkin's and Auerbach's method of treatment upon considerable quantities of artificial alizarin. We first followed out Perkin's method, and obtained a product corresponding in all respects with his description of anthrapurpurin. We then worked on another quantity of artificial alizarin according to Auerbach's directions, and when we came to the last treatment, namely, solution in and crystallisation from alcohol, we found that we evidently had to do with a mixture of two bodies differing in a marked way as to their solubilities.

Bearing in mind that we had found Perkin's anthrapurpurin but little soluble in alcohol, and that Auerbach described his isopurpurin as quite soluble, we só carried on the alcohol treatment as to reserve the soluble part as isopurpurin and reject the less soluble portion.

When we had carried this separation to a sufficient extent, we found that we had a body entirely distinct from Perkin's anthrapurpurin, but sufficiently like the description given by Auerbach of his isopurpurin to answer for it when due allowance was made for the uncertainties of a verbal description. When, however, the paper of Schunck and Roemer appeared in 1875, we saw that the body we had extracted agreed still more closely with their flavopurpurin.

Having obtained it, however, by the process described in 1872 by Auerbach, I still continued to call it by his name, and should do so still had he not very emphatically repudiated all credit for and connection with it.

The true relation of the substances which have borne the names given at the head of this article is, then, this :Anthrapurpurin is a single substance, first isolated by Perkin, partially in 1870, and thoroughly prior to June 6, 1872.

Isopurpurin is a mixture, in proportions varying according to the composition of the artificial alizarin from which it is extracted, and the way in which the alcoholic treatment is conducted, of anthra- and flavopurpurin with a trace of alizarin. This mixture was first separated and described by G. Auerbach in August, 1872.

Flavopurpurin is a single substance or chemical individual first isolated and described by Schunck and Romer in the Ber. der Deut. Chem. Gesell., 1876, p. 678.

The facts as to the composition of the material obtained by treating artificial alizarin by the method described by Auerbach are also established by the recent researches of M. A. Rosenstiehl, presented to the Chemical Society of Paris, and published in the Bulletin of that body of May 5 and 20, 1878, where, in vol. 29, p. 408, I find as follows:

256

(CHEMICAL NEWS,

June 13, 1879.

The material so purified was then dissolved in boiling alcohol, and allowed to deposit crystals on cooling. The author then continues:

"Comparative dyeing tests with the part crystallising out and with that remaining in the mother-liquor showed that the alcohol eliminated a substance colouring mordants live flavopurpurin, that is to say, of a red more orange than that of oxanthraflavon."

It should be mentioned that in this essay its author indicates by the word oxanthraflavon the material isolated by Perkin's method, but which through oversight of the earlier publications he credits to Auerbach, and nanies isopurpurin in consequence of this mistake.

ON THE

COMPOUNDS OF THE TERPENES WITH HYDROCHLORIC ACID.

By WILLIAM A. TILDEN.

IN the course of researches which I have for some time been pursuing into the constitution of the terpenes I have had occasion to prepare and examine the compounds which these hydrocarbons form with hydrochloric acid. The following is a brief account of the chief results arrived at in this direction, and as they possess some interest at the present time, I think it desirable to place them on record. When dry hydrochloric acid gas is passed into cooled turpentine oil (b.p. 156°), whether from American or French turpentine, the well-known mono-hydrochloride, C10H17Cl, is obtained, melting at 125°, and boiling at about 210°. It is accompanied by liquid products, which yield a large quantity of the same hydrochloride on distillation. This liquid consists of a mixture of cymene, always present in turpentine oil, with liquid compounds of the mono-hydrochloride and di-hydrochloride. The fact that the two chlorides when mixed together unite and liquefy was originally pointed out by Berthelot, and I can confirm this observation. The existence of a liquid modification of the mono-hydrochloride is doubtful. The solid monohydrochloride is also produced if the turpentine is diluted with benzol or carbon bisulphide before submitting it to the action of the gas.

The result is different when the turpentine is saturated with hydrochloric acid in the presence of some liquid which contains water, or is capable of yielding the elements of water. Thus, when the same turpentine oil is diluted with alcohol, ether, or glacial acetic acid, it yields a deep purplish coloured liquid, which, after exposure to the air for some time, deposits crystals of the di-hydrochloride, C10H18C12. But it deserves to be noticed that when once the terpene has been made to unite with one molecule of hydrochloric acid no further action of the gas, either in the dry state or in presence of any of the solvents named, is capable of causing it to combine with a second molecule so as to produce the di-hydrochloride. There can be no doubt that these two chlorides are of entirely dissimilar constitution, as they behave quite differently under the influence of alkalies, the mono-hydrochloride being decomposed with difficulty by soda, yielding a crystalline camphene, whilst the di-hydrochloride produces chiefly terpinol, C10H17(OH). The di-hydrochloride referred to possesses the same properties, whether prepared from lavo- or dextro-gyratory turpentine oil. Its solution in alcohol is optically inactive. The crystals melt at 48° in an atmosphere of hydrochloric acid, and by heat are readily decomposed into hydrochloric acid and a hydro. carbon. This di-hydrochloride is also obtained by the

If in place of turpentine oil one of tne terpenes of higher boiling-point is operated upon no mono-hydrochloride can be obtained. Thus, the terpene from orange oil boiling at 176° was dried and saturated with hydrochloric acid. The resulting solution was colourless, and after exposure to the air for a day or two was found to contain no chlorine at all. But when the same terpene was mixed with ether, and treated with the gas, a solid mass of colourless crystals remained after evaporation of the ether. It was a somewhat unexpected discovery that these crystals consist of the same di-hydrochloride already described, that is obtained under the same circumstances from turpentine. There is, however, some difference observable in the behaviour of the terpene from the orange and those from the turpentine oils; for whilst the former yields a nearly theoretical amount of crystallised dihydrochloride, the latter produce a considerable quantity of liquid of deep colour. This colouration is characteristic of the action of hydrochloric acid upon terpinol, C10H180, or C10H17OH, as shown in a recent paper (Journal of the Chemical Society, June, 1879), and it appears to indicate the formation of an intermediate product which is probably the same in both cases.

In order further to establish the identity of the dihydrochlorides thus obtained from the two classes of terpenes, the dichloride prepared from the orange oil and from turpentine oil were decomposed by water. 50 grms. of each boiled with 500 c.c. of water were found to be decomposed at the same rate and in the same manner, yielding a mixture of hydrocarbon (terpinylene, C10H16, b.p. 176o), and terpinol (C10H180, b.p. 210°). The terpinol was recognised in each case by its conversion into crystallised terpin by the action of sulphuric acid and water. The terpenes from juniper oil (b. p. 156°), lemon (b. p. 176o), bergamot (b.p. 176°), and caraway (b. p. 176°) yield this di-hydrochloride, as also does the terpene (b. p. 174° to 176°) contained in the ol. pini sylvestris of pharmacy and a terpene (b. p. about 176°), obtained from rosin spirit. The single exception is the "sylvestrene " discovered by Atterberg in Swedish turpentine, and which I have since recognised in Russian turpentine. The di-hydrochloride which this terpene yields melts at 72° to 73°, and although decomposed by alkali it yields a hydrate which is apparently not common terpinol. If it should prove to be distinct from ordinary terpinol it is probable that it may be convertible into a new terpin. I am about to make experiments with the object of settling this question, which possesses some interest.

The terpene di-hydrochloride described in this paper is decomposed by simple application of heat, and by prolonged boiling in a flask fitted with condensing tube is resolved into hydrochloric acid and a hydrocarbon, terpinylene, C10H16, which boils at 176°. A portion of the hydrocarbon is at the same time converted into viscid polymerides. Terpinylene cannot, however, be made to recombine with hydrochloric acid so as to reproduce the crystalline di-hydrochloride.

Thus terpenes of the two classes, boiling respectively at 156° and 176°, and very diverse in their optical properties, may all, by this process, be converted into one and the same inactive hydrocarbon.

I cannot conclude without expressing my thanks to Mr. G. H. Morris and Dr. G. Harrow for valuable assistance in these experiments and in other parts of the same research.

The Paris Academy of Sciences.-At the sitting of the Academy on Monday last Professor G. G. Stokes, M.A., D.C.L., LL.D., Secretary of the Royal Society, was elected a corresponding member in the Physical Section in succession to the late M. Angström.