Obrazy na stronie

Formation of Hydrocyanic Acid in the Electric Arc.


June 27, 1879. the case of the odd members of the first group this may, that the colours are so produced and are not due to be explained by the fact that it is very uncertain whether interference. Cu, Ag, and Au really belong to the same group as Na or I have sent, for the Society's inspection, pictures of the not, as pointed out by Mendelejeff in his memoir on the solar spectrum on silver plates, and also on compounds " Periodic Law,” in which he places these elements not of silver held in situ by collodion. It will be observed in the first group along with Na, but in the eighth with that the spectrum has imprinted itself in approximately Fe, Pd, Pt, &c.

its natural coluurs ; that on the silver plates it is more As far as existing data allow us to judge, the compounds brilliant than on the collodion film, but that in the latter of the elements with monatomic organic radicals also the colours are seen by transmitted as well as by reflected obey the same laws as those of the halogen compounds. light.

A process for calculating unknown melting-and boiling. I reserve for the present the exact details of the propoints in the case of halogen compounds) by a method duction of these picures, but may say that they are proof limits is next described, which gives very good results duced by oxidation of silver compounds when placed in when applied to known melting- and boiling points, the the spectrum; an exposure of two minutes being amply average error for all known boiling - points being sufficient with a wide slit to impress the colours. The

+ + 4'5° C., or o.8 per cent, and for all known melting colouring matter seems to be due to a mixture of two points £15, or 3 per cent. The calculated values for a different sizes of molecules of the same chemical compo. large number of unknown melting- and boiling points are sition, one of which absorbs at the blue end and the other given.

at the red end of the spectrum, and the sizes of these It is also shown that a knowledge of the melting- or molecules are unalterable whilst exposed to the same boiling points of the halogen compounds of an element wave-lengths as those by which they were produced. I may serve for the determination of the atomic weight believe it possible and probable that the colours may be when the application of the methods of specific heat and preserved unchanged when exposed to ordinary daylight. vapour-density are inadniissible, or the results obtained by these contradictory.

An application of this is made in the case of beryllium, concerning the atomic weight of which there has recently ON THE FORMATION OF HYDROCYANIC ACID been some dispute. From his determination of the

IN THE ELECTRIC ARC.* specific heat of the metal, Emerson Reynolds concludes that it is a dyad with atomic weight 9:2, whereas Nilson By JAMES DEWAR, M.A., F.R.S., Professor of Chemistry to the and Petterssen, from their determination of the specific

Royal Institution. heat, assign to it the atomic weight 13.8, in which case it would be trivalent. Now, according to calculation, the melting-points of the chloride, bromido, and iodide of A series of experiments favouring the conclusion that beryllium ought to be (820° to 870°)," (802 to 820"), and the so-called carbon lines are invariably associated with (766' to 770°) respectively. The boiling-points, also,

the formation of acetylenet induced me to make some ought to diminish from the chloride to the iodide, ii experiments to ascertain whether this substance can be beryllium is a dyad with atomic weight 9'2. If it be a

extracted from the electric arc, which invariably shows triad with atomic weight 13.8 these melting points ough this peculiar spectrum at the positive pole, when it is to be about 500° lower, and the melting- and boiling the carbons were used in the form of tubes, so that a

powerful and occasionally intermittent. For this purpose points ought to increase from the chloride to the iodide. With the object of settling this point the melting points through either pole, and the products thus extraded from

current of air could be drawn by means of an aspirator of the chloride and bromide have been carefully deter: the arc collected in water, alkalies, and other absorbents. mined, and it was found that the chloride melts at 858° Gases may be led through one of the poles, and suđion into 890°, thus agreeing with the limits (8200 to 870°) cal. duced through the other, in order to examine their effed on culated for BeCl2 (Be=9:2) The bromide also fuses

the arc. between 858° and 890°, and at almost exactly the same temperature as the chloride, but if anything slightly by means of the Siemens and de Mériten’s magneto

The following experiments record the results obtained higher, the calculated number for BeBr2 being 802° to

machines :820°. The rather high number found for the bromide is probably due to the substance being so readily volatile

Experiment 1.- Drew a current of air by an aspirator below its melting point that the heat absorbed during through the drilled negative carbon, and passed the gases conversion into vapour cools the remainder of the solid, through potash, and iodide of potassium, and starch and thus prevents it melting so soon as it otherwise would paste; found no nitrites; potash contained sulphides. do. These results confirm the view that beryllium is a

Experiment 2.-Hydrogen led in by the positive pole dyad, with atomic weight 9-2; for, though the melting and the gases extracted as above, gave the well-known point of the bromide is apparently slightly higher than acetylene compound with ammoniacal sub-chloride of that of the chloride, for the reason already given, yet copper; while at the same time, a wash-bottle containing BeBr2 is far more volatile than BeCl2.

water gave distinct evidences of the presence of hydrocyanic acid.

Experiment 3.-Hydrogen Aame burning alone gave

no sulphides or hydrocyanic acid, the condensed water ON THE PRODUCTION OF

in a small bulb gave nitrites.

Experiment 4.-Air drawn through the negative carbon COLOURED SPECTRA BY LIGHT.

gave considerable quantities of hydrocyanic acid, which By Captain ABNEY, R.E., F.R.S.

was greatly increased by extracting the gases through the positive carbon. Air was aspirated at the rate of about

one litre per minute. Last year 1 incidentally mentioned in a note to the Experiment 5.— The same carbons used with de Mériten's Royal Society (Proceedings, vol. xxvii., p. 291) that the magneto-machine gave no result. production of natural colours by the agency of light, Experiment 6.-Čarbons purified in chlorine and hydroexamples of which were shown by Becquerel, was probably gen gave with de Mériten's nothing; with Siemens's and caused by the oxidation of silver compounds employed. I å draught of air through the negative pole, a small I have ventured to return to the subjeđ in order to show quantity of hydrocyanic acid, but a larger yield when Reckoned from absolute zero - 273.

* A Paper read before the Royal Society, June 19, 1879, + A Paper read before the Royal Society, June 19, 1879.

+ As suggested by Pucker, Angstrom, and Tbalén.

On Gardenin.

283 June 27, 1879. positive used. The gases extracted after the absorption tion with tannin till aided by vapour of carbonate of of the hydrocyanic acid contained acetylene. If the car- ammonia, when the usual purple colour of ferric tannate bons are not purified, sulphuretted hydrogen is always was developed. There is thus evidence of the deposit found along with other gases.

containing platinum, carbon, and iron. Probably the The inference to be drawn from the above experiments scattering of platinum globules might result from the is that the high temperature of the positive pole is re- disruptive discharge which took place at the moment of quired to produce the reaction, which is in all probability the lamp breaking down. the result of acetylene reacting with free nitrogen, as when induction sparks are passed through the mixed gases, viz., C2H2+N2=2HCN, and that the hydrogen is obtained from the decomposition of aqueous vapour, and the com- PROCEEDINGS OF SOCIETIES. bined hydrogen in the carbons. It is possible, traces of alkaline salts in the carbon poles may favour the formation of hydrocyancic acid, but, as all attempts to purify the

CHEMICAL SOCIETY. poles so as to stop the reaction failed, I am inclined to believe it is a direct synthesis. The acetylene reaction

Thursday, June 19, 1879. is one of the many remarkable syntheses discovered by Prof. Berthelot of Paris. The presence of sulphuretted

Dr. Roscoe, Vice-President, in the Chair. hydrogen is doubtless due to the reduction of the sulphates, invariably present in the ash of the carbon.

A more complete examination of the various reactions The minutes of the last meeting were read and confirmed. to be brought about by means of the Siemens arc, and The following certificates were read for the first time :with poles of varied composition, and in presence of 1. W. Smith, W. R. Eaton Hodgkins, J. R. Ashwell, J. different gases, will be communicated to the Society in a

Bemrose. During the evening the following gentlemen subsequent paper.

were ballotted for and declared by the scrutators, Messrs. My thanks are especially due to Messrs. Ausdell and Carteighe and Tribe, to be duly elected Fellows of the Cottrell, assistants in the Royal Institution, for their Society ;-C. J. Wilson, R. Reid, G. R. Tweedie, W. T. valuable aid.

Bayne, J. Fletcher, H. Appleby, J. Sakurai, A. E. Robinson.
The following papers were read :-

011 Gardenin," by J. StenHouse and C. E. Groves. ON THE SMOKE OF AN ELECTRIC LAMP.*

A short note on this substance was published in the

Society's Journal some time ago by the authors, in which By B. S. PROCTOR.

they described the method of extracting this substance

from the so-called “Dekamali gum,” which is the resinous At our meeting in December, 1878, Mr. J. W. Swan compound by the action of nitric acid. In the present

exudation from Gardenia lucida ; they also obtained a red exhibited an electric lamp, on the incandesence principle: paper the authors continue the above investigation. The which had broken down in consequence of the electric resin of the Gardenia lucida has a peculiar and unpleasant force being too great for the cylinder of carbon through alliaceous odour, which is undoubtedly due to some which it had to pass. A note on this subject appears in volatile compound. By distilling the resin in a current the current part of our Transactions, p. 190. One of the of steam a volatile oil came over. The bulk of this dispoints of interest noted was the appearance of a sooty tilled at 170°, and, after rectification over sodium, yielding deposit on the inside of the glass. The flask which con. tained the carbon pencil and its platinum conductors, small quantity of the oil boiled at 250°. The residue con

a terpene boiling at 160°, having the formula CjH16; a Sprengel pump, was supposed 10 contain nothing which sisted of a dark brown liquid, having an aromatic and could act as a carrier to convey by chemical means any Details of the methods employed for extracting and

slightly alliaceous odour, and containing a trace of sulphur. carbon from the incandescent pencil to the cooler surfaces purifying the gardenin are given in the paper. The pure in its neighbourhood. The phenomenon appeared to be substance has the formula C14H1206. On treating a part such as has been spoken of under the term “ volatilisa. of finely divided gardenin with 10 of nitric acid, sp; gr. tion of carbon.” Mr. Swan having placed the lamp at my 1:24, keeping the mixture cool, the whole turns of an disposal for examination, I have now the pleasure of orange colour, and finally solidifies in a few minutes to a bringing under your notice the results.

Under the microscope the smoky deposit on the glass paste of bright red needles, which are collected, washed showed numerous bright globules, no doubt platinum, rapidly: to prevent further decomposition, dried, and and more minute particles of dark matter nebulous under crystallised from boiling chloroform; this substance has

been provisionally named gardenic acid, though the a X-inch objective.

authors have no evidence that it is really an organic acid, A fragment of the glass exposed to an oxidising heat, its behaviour with reducing agents pointing rather to a the deposit partially disappeared, still leaving the glass quinon grouping. It is insoluble in water, light petroleum, slightly darkened. dark sublimate at a little distance above and below the with a deep yellow colour, being re-precipitated on the The platinum support-which had also a coating of and carbon bisulphide, and almost insoluble in ether and

benzene; dissolves readily in cold dilute alkaline solutions carbon pencil, but not in immediate juxtaposition with the unsmoked portion, so that the conducted heat might nitric acid is added to a cold supersaturated solution of it- was next examined by exposing to the blowpipe fame addition of acids ; its formula is Č14H1006; it melts with

decomposition at 223o. When a small quantity of strong ad upon the deposit without the fear of the blast carrying gardenin in glacial acetic acid, a mass of crystals

of garaway the matter, which was very loosely attached. In Senic acid is obtained. If, however, this product, after this way the deposit was burnt off without the mechanical being washed and dried, is boiled for some time with ađion of the blast, the heat to which it had been subjected glacial acetic acid and re-crystallised from that solvent, it being that of dull redness. A piece of the glass was then treated with aqua regia dissolves in alkaline solutions but sparingly in the cold,

becomes more orange-coloured and melts at 243', and for several days. The deposit was diminished, but far yielding a purple solution, turning pale red on boiling. from

being entirely dissolved; the solution gave a blue This acetyl compound dissolves readily in boiling alkalina reaction with yellow prussiate of potash, and no coloura solutions, from which it is precipitated by acids ; it has • A Paper read before the Newcastle-upon-Type Chemical Society, ' in contact with dilute nitric acid, sp. gr. 1*24, for a con

the formula C14H806(C2H30)2. When gardenin is left March 27, 1879

Terpenes, Camphor, and Allied Compounds.


June 27, 1879. siderable time, gas is evolved, and a bright orange-coloured composition referred to by Mr. Wanklyn was the metallic substance is formed, which is seen by the microscope to impurities present in ordinary zinc dust, lead, &c. consist of colourless crystals mixed with an orange amor. Dr. ARMSTRONG then read a paper by Dr. Tilden and phous substance. The crystals are soluble, the amorphous himself on The Action of Sulphuric Acid on the Hydrosubstance insoluble in water. In contact with an aqueous carbons of the Formula C20H16." The authors describe solution of sulphurous acid, gardenic acid acquires a many experiments on the action of sulphuric acid of bright yellow colour and is converted into hydrogardenic various strengths and at various temperatures, chiefly on acid, C14H1406; it forms flat lustrous needles resembling the terpenes of American and French turpentines. The lead iodide; it melts at 190°, and is insoluble in water, so-called terebene can be best prepared by using concen. light petroleum, and carbon disulphide, sparingly soluble trated acid at about 80° to 90°; at lower temperatures in ether, easily soluble in hot benzene, spirit, or glacial much polymerisation takes place. The distillate obtained acetic acid ; it dissolves in dilute alkaline solutions, from by passing steam through the product of the above a&ion which it is precipitated by acids; oxidising agents recon- | is not, as Ribau has stated, a mixture of cymene with an vert it into gardenic acid. Further researches as to the optically inađive liquid isomeride of terperse; the soconstitution of gardenic acid and gardenin are promised. called terebene being really ina&ive camphene. By long

"On Dry Copper-zinc Couples and Analogous Agents," fractional distillation it is obtained as a crystalline solid, by J. H. GLADSTONE and A. Tribe. The authors, in melting after crystallisation from alcohol at 47o. The order to avoid the time, trouble, and the use of alcohol and distillate contains also much of a CsoH16 hydrocarbon, ether necessary for the formation of the ordinary zinc boiling at 176°, which is terpilene. The product of couple prepared by immersing zinc soil in a 2 per cent the adion of dilute sulphuric acid on terpene is terpilene solution of copper sulphate, &c., have turned their atten. without camphene. The crude colophene which is not tion to the production of a dry couple as active as the carried over by steam yields on distillation 10 to 30 per moist couple. After numerous experiments the following cent of substances volatile in steam, principally inadive method was found to be most satisfactory :-9 parts by camphene and terpilene, also cymene, a small quantity weight of coarse zinc filings are placed in a dry flask with of a paraffin-like body, an optically inactive camphol I part of finely divided copper ; the mouth of the flask is (borneol), C10H170H, &c. then closed by a cork, through which passes a tube having "Researches on the Terpenes, Camphor, and Allied Com. a capilliary termination. The metals are mixed and pounds" (Part I.), by Dr. ARMSTRONG. On Hydrocarbons heated in a Bunsen Aame with continuous shaking until associated with the Terpenes, and on the Formation of the filings begin to lose their shape and acquire a yellowish Cymene from Terpenes and Allied Compounds.– A sample tinge; the mixture is then somewhat rapidly shahen first of terebene, given to the author by Dr. Hugo Müller, conin and then out of the flame. If the operation has been sisted almost entirely of cymene and of a paraffin-like successful a number of small dark gray granular masses body, boiling at 170°, but having the composition C10H20are obtained. The state of division of the copper is of On treating various terpenes with sulphuric acid similar great importance; the authors recommend the copper results were obtained, in most cases 3'5 per cent of cymene obtained by reducing the protoxide at the lowest possible and oʻ5 per cent of the hydrocarbon insoluble in concen. temperatuie in hydrogen and sifting the product through trated sulphuric acid. Russian turpentine contains fine muslin. 10 grms. of a dry couple prepared as above 8 per cent cymene and 2 per cent of the hydrocarbon. convert 5 c.c. of ethyl iodide into zinc ethiodide in about Terpilene, resin spirit, the distillate from india-rubber, six minutes when heated to go® C. The authors in one that from colophene, contain much cymene, with this in. experiment employed 87 grms. of ethyl-jodide, with a pro soluble in sulphuric acid) hydrocarbon. The author portionate quantity of couple; in fifteen minutes a con. believes the reaction 3C10H16=2C101114+C10H20 takes version equal to 90°4 per cent of the theoretical amount place under these circumstances. had taken place. The authors have, in the second por. Part II. On the Action of Iodine on Terpenes.-The tion of the paper, investigated the action of other couples. product obtained by distilling turpentine with one-fourth Zinc and platinum form a couple which decomposes its weight of iodine is not merely cyme ne or so complex water more energetically than the copper-zinc couple. In as the product of Preis and Raymann (Ber. der Deutsch., the preparation of dry couples no combination was found xii., 219). It contains 33 per cent of hydrocarbons in to be superior to the copper-zinc combination, probably soluble in sulphuric acid, apparently a mixture of two because the copper sticks better to the zinc than either hydrides of the formula C10H20, boiling at 160° and at 170°. platinum, silver, or gold; it is also less liable to form The portion soluble in acid contains no appreciable amount alloys with zinc than these three metals. Magnesium of lower homologues of cymene, but consists of camphene, and platinum form an exceedingly active wet couple, but cymene, and higher homologues. A small quantity of an effective dry couple could not be obtained. Zinc with what appears to be a mixture of methyl and ethyl iodides either cuprous or cupric oxide forms a dry couple almost is also produced in the reaction. equal in activity to that formed by zinc and metallic Part III. Camphor Derivatives," by Dr. ARMSTRONG copper... The authors conclude that for practical purposes and Mr. Matthews. The body previously described, as no combination is superior to that formed with zinc and formed with camphoric acid by heating bromo-camphor copper prepared as above described.

with nitric acid, is a nitro-deriva ive. Dibromo-camphor In answer to Mr. GROVES,

yields no camphoric acid on oxidation with nitric acid, Dr. GLADSTONE did not think that any difficulty would but is slowly and completely decomposed ; alcoholic potash be found in preparing zinc-ethyl on a manufacturing scale reduces it to mono-brom-camphor. Chlorine at 100° conwith the aid of the copper-zinc couple.

verts camphor into mono- and dichlor-camphor. The Mr. WANXLYN had been much struck with the state. former resembles bromo-camphor in its behaviour with ment of the authors that when the copper and zinc were nitric acid; heated with alcoholic potash it retains its alloyel the couple so formed was inactive; it seemed to chlorine, and exchanges its hydrogen for hydroxyl. With him that some slight alteration of the surface of the zinc bromine, chloro-camphor yields å magnificently crystalwas at the bottom of these reactions. Some long time line bromo-chlor-camphor; these bodies resist oxidation. ago he had left some ethyl-iodide in contact with ordinary The above nitro-derivatives with alcoholic potash give zinc dust for some time in sealed tubes at the ordinary potassic nitrite and hydroxy derivatives. Todo-camphor is temperature: on opening them the conversion was found readily prepared by the action of iodine chloride on cam. to be almost complete. The late Mr. Chapman and phor. Mixed iodo-derivatives are also obtained in the himself had observed tha: magnesium amalgam decom. same way. posed water, whereas sodium amalgam was comparatively After a few remarks by Dr. Wright, inactive.

Mr. H. F. Brown read an abstract of a lengthy paper by Dr. GLADSTONE suggested that the cause of the de- / Mr. HERON and himself, entitled “Contributions to the

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June 27, 1879.
The Purple of the Ancients.

285 History of Starch and its Transformations." The experi- | dextrin : the remaining changes are given in the lol. ments were conducted with we!l-wash:d and purified lowing table :potato-starch. The transforming agent used was a cold,

First power. Copper oxide Resulting filtered, aqueous infusion of malt, made by acting upon

Degrees. reducing power. dextrin. 100 grms. of finely.divided pale malt with 250 c.c. of water. Soluble starch 2160 The total solid matter is deduced from the specific gravity,


Erythrodextrin, a a constant divisor 3.86 being used. The starch granule


B consists of granulose and starch cellulose, the latter pre

195'4 189

Achroodextrin, a ponderating in the outer layers. Starch cellulose can be

18807 2542

B obtained by acting upon starch paste in the cold with un

182'1 3143 heated normal malt extract. The granulose rapidly dis

175.6 3783 solves, leaving most of the starch cellulose behind. When


169'0 }

433 once separated in the insoluble form this substance cannot


49'3 again be brought into aqueous solution without decompo.


156-3 55'1 sition; it is also unattacked by malt extract. On boiling Maltose


610 with water it is chiefly converted into soluble starch, which has probably no action on polarised light. The The authors have established the existence of Nos. 2, 3. viscosity of starch paste varies much with the previous 4, and 8, and have indications of 5 and 6; No. 8 is the treatment of the starch. The specific rotatory power of most stable. Dextrose is not a product of the action of malt starch paste equals 201•1° to 202.1°. The specific rotatory extract upon starch, the hydration ceasing with the com. powers of granulose and soluble starch are identical. With plete conversion into maltose. Diastase is a function of potash, the specific rotatory power of granulose is the coagulable albuminoids of malt extract, and does not 169'4°10 174.2°, and of soluble starch 182.6o. The maltose consist of any particular principle. The albuminoids of used was prepared by acting on starch with malt extract, barley resemble those of malt, but are less active. The and crystallisation from alcohol. Its specific rotatory albuminoids of barley precipitated above 60° are inadive as power was 150°4°; its cupric oxide reducing power was regards diastatic aâion. During germination the consbro. By the action of dilute sulphuric acid a dextrose paratively inactive albuminoids of barley have conferred identical with that of invert sugar was obtained. The end upon them a large amount of potential energy. The product of the readion had a specific rotatory power of growing yeast cell is capable, to a certain extent, of imi. 58.6°, and a cupric oxide reducing power of 100-2. Maltose tating the modifications induced by the living vegetable is unacted upon by continued digestion with malt extract cell in the ordinary process of germination. at 5uo to 65. c. As the outer layer of the starch granule The next paper was read by R. WARINGTON, “ On the consists of insoluble starch cellulose, the granulose cannot Determination of Nitric Acid by means of Indigo, with espebe dissolved by any converting agent which is not diffu. cial reference to Water Analysis.” The indigo method pos. sible, and which does not at the same time transform ic sesses the advantages of great simplicity,speed, and delicacy. into diffusible products ; so the intact starch granule can The results are, however, conditioned by many circum. be digested with malt extract, the transforming agent of stances, which must be known before the method can be which is colloidal, at ordinary temperature without a&ion. applied with accuracy. A solution of pure indigotin is If, however, the granules are ruptured by trituration with much superior to the sulphindigotate of sodium usually sharp quartz sand a rapid adion is set up. Starch cellu: | employed, the former giving a pale colour when oxidised lose at first enters into solution, afterwards maltose and by nitric acid, and thus allowing a small excess of indigo dextrin are formed. The action of malt extract on starch to be readily seen. The estimation is made as follows : paste is very rapid ; in about three hours the specific 20 C.C. of the water are mixed with the indigo solution, rotatory power attains a maximum of 161.6°; the cupric and pure oil of vitriol, equal in volume to the united water oxide reducing power also reaches a maximum at the same and indigo, suddenly added. The whole is then placed in time, = 4997. The modifications of this reaction at elevated

a chloride of calcium bath at 140° till the reaction is comtemperatures depend much more on the previous treat. pleted. The quantity of indigo corresponding to the ment of the malt extract than upon the actual degree of nitrate present is found by a series of approximating expe. temperature at which the transformation is made; this fact riments. In weak solutions the quantity of indigo oxidised has been noticed by O'Sullivan. The authors state in is not strialy proportional to the nitrate present. If a general terms that “if two different transformations of solution of nitre requires 10 c.c. of the indigo solution reequal quantities of starch are brought about at different commended in the paper a nitre solution of one-eighth of temperatures by equal quantities of a malt extract which the strength will require only 1 c.c. The indigo must has been heated for a few minutes to a point identical with therefore be standardised with nitre solutions of graduated or higher than the more elevated of the two temperatures strengths, and a table of the value of the indigo scale conof transformation, then the conversions will be similar in structed, by which subsequent analyses can be calculated. every respect." To investigate the various stages of the Some attention must be paid to the initial temperature of action more thoroughly it was necessary to be able to the solutions : a rise from 10° to 22° is attended with a arrest the reaction at any desired moment. This was done diminution of 5 per cent in the indigo oxidised. Chloby pouring the sample into a small Aask containing a few rides have some infuence; a water containing 17.8 centigrms. of salicylic acid. The authors then give tables per million of nitrogen would yield 1705 in the presence of and curves illustrating the action of malt extract upon much chloride, while a water containing 4'3 would give starch paste at various temperatures and under varying 4'5; the error is thus in opposite directions for weak and conditions. Throughout these transformations the specific strong solutions. Nitrites cannot be determined by in. rotatory power and the cupric oxide reducing power of the digo ; they oxidise less indigo than nitrates, and give no products agree closely with the supposition that maltose sharp reaction; they must be converted into nitrates by and dextrin are the only substances formed in the reaction. permanganate before employing indigo. Some kinds of When the products of a transformation of starch having organic matter greatly diminish the amount of indigo oxia united optical activity higher than 162.5° are treated with dised, and the soluble organic matter of soils affects the a little unheated malt extract at 50 to 60 the specific rota results in this manner. Analyses of waters by Frankland's tory power falls at once to 162.5°; this change takes method and the indigo process give closely concordant place per saltum and not gradually. The most probable results formula of soluble starch is 10(C12H20010). The first aâion of the transforming agent of malt extract is the

The following papers were taken as read :hydration of one (of the ten) C12H20010, and the conse- Notes on the Purple of the Ancients," by EDWARD quent produ&ion of maltose, the nine left forming erythro. SCHUNCK. This colour, which was extracted by the

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CHEMICAL NEW, Boiling-points of certain Metals and Metallic Salts.

June 27, 1879. ancients from various kinds of shell-fish, and applied to

Calories evolved, the dyeing of linen and woollen fabrics, bas excited much


2747 interest from time to time. The author gives a résumé of


5753 previous work on the subject. Cole (Phil. Trans., 1865)


-8084 disccvered a shell-fish in Somersetshire which yielded a


- 1364 purple dye. Reauniur in 1710 discovered a similar species


5985 (Pupura lapillus), Dutramel in 1736, and Bancroft in 1803, Toluydine

1281 also worked at the subject. Their results may be summarised


7184 as follows:-1. The colour-producing secretion resembles


7117 pus, and is contained in a small whitish cyst under the shell

Pyrrol ..

4056 close to the head of the animal. This pus-like matter "On Ethylenic Chloro-sulphocyanide and its Oxidation when applied to white linen and exposed to sunlight into Ethylenic Chloro-sulphonic Acid," by J. W. James. changes from yellow, through light green, dark green, 66 grms. of potassium sulphocyanide were placed in a blue, to purplish-red or crimson, a strong odour resembling flask with about 250 c.c. of 98 per cent alcohol ; after garlic or assasætida being evolved. Daylight is essential; shaking, 100 grms. of chloro-bromide of ethylene prepared if kept in the dark the secretion remains unchanged for by Lössner's method were introduced, and the mixture years, and then on exposure to light becomes coloured. heated on a water-bath ; decomposition rapidly ensued. Heat does not promote the change which proceeds in Potassium bromide and chloro-sulphocyanide of ethylene vacuo or in hydrogen or nitrogen gas. The colour resists were formed; the latter substance after purification was the action of soap alkalies and most acids; it is destroyed obtained as a colourless oil, of a disagreeable smell by nitric acid and chlorine. A. and G. de Negri have resembling that of oil of mustard ; it affects the eyes, does récently obtained two colouring matters from a species of not excite sneezing, it boils at 202° to 203° C., its vapour murex; one is blue and presents the characters of india burns with a violet coloured Aame. Analysis gave the gotin, the other is red, but its nature is not certain. The formula C2H_CI(CNS). By oxidation with fuming nitric author has made many experiments with Purpura lapillus, acid, chloro-ethylen sulphonic acid is obtainedwhich he obtained on rocks at low water near Hastings, live animals alone being used. The pale yellow secretion

C2H,CI(SO3H); turns purple when exposed to light without being applied the author has prepared and analysed the barium and to linen. Boiling does not hinder the production of the silver salts. By heating the silver salt with ammonia colour. The author observed the change of colour under in sealed tubes to 100° to 120° C. about 0.7 grm. of pure the microscope. The chromogen can be completely ex

taurin was obtained, according to the following equationtracted by alcohol and ether from the pounded cysts, a golden solution being obtained, which becomes purple on

C2H_CISO3Ag+NH3=C2H<S0zł + Agcl.

-NH2 exposure to light, a purple powder being ultimately pre.

On the Boiling-points of Certain Metals and Metallic cipitated, which is granular and crystalline. Hydro- Salts," by T. Carnelly and W. Carleton WILLIAMS. chloric acid produces a decomposition somewhat similar in a previous communication the authors described a to that effected by sunlight, a purple colour being formed. simple method of measuring the temperature of ebullition The author worked up the cysts or veins from 400 animals, of those bodies whose boiling points are beyond the range and obtained 7 milligrms. of the purplish powder by ex.

of the mercurial thermometer, by observing whether certain posure to sunlight. It was insoluble in water, alcohol, salts whose melting points are known melt on exposure and ether; slightly soluble in boiling benzol and boiling to the vapour of the boiling substance. In the present glacial acetic acid; easily soluble in boiling aniline, the solution giving a broad absorption band between Cand D. paper they give results thus obtained :-Palmitic acid, Heated between watch-glasses, a sublimate of crystals 339° to 356o ; stearic acid, 359° to 383°; selenium, 676° to

6830; tellurium dichloride, 327° ; tetrachloride, 414°; with metallic lustre showing at their edges a deep indigo- teirabromide, 414° to 427°; stannous chloride, 617° to 628°; blue colour. The colouring matter dissolves in strong bromide, 617° to 6340 By using pure metals instead of sulphuric acid to a purplish solution, showing a bond salts of known melting points the following numbers were between D and E. From these reactions the author con

obtained :-Lead chloride, 861° to 1000°; cadmium chloride, cludes that the colouring matter belongs to an unknown 86ro to 1000°. Glass tubes are rapidly corroded by molten member of the indigo-blue group, and proposes to call it potassium and sodium, iron tubes were therefore used. Punicin. The liquid from which the a&ion of sunlight Sodium, 861° to 10000; potassium, 719° to 731° ; bismuth, had precipitated the purple powder contained no glu- rogoo to 1600°; lead, 1600° to 1800°; tin, 1600° to 1800°;

antimony, 1090° to 1600°. The authors point out a curious "On the Heat of Formation of Aniline, Picoline, relation between the melting and boiling point of CI, Br, Toluydine, Lutidine, Pyridine, Dipicoline, Pyrrol, Glyce- and I and those of S, Se, and Te; for the melting points rine, and Furfurol,” by W. RAMSAY. In a recent paper of the S, Se, and Te are respectively twice and the boiling. on the volumes of liquids at their boiling points the points three times as high as those of Cl, Br, and I, all author remarked that some connection might exist be being reckoned from the absolute zero --273° C. Thus:tween the ebullition volume of a liquid and the amount of | Melting points of heat evolved during its formation. The present paper Chlorine 198° X 2 = 396° Sulphur melts contains an account of the method used to determine the Bromine 251 X 2 = 503 Selenium heat evolved and the results obtained. The method em- Iodine 380 x 2 = 760 Tellurium 755 to 773 ployed was an indirect one; the amount of heat evolved by Boiling points of the combustion of the elements of a substance was calcu- Chlorine 240°x3= 720° Sulphur boils

720° lated; the amount of heat evolved by the combustion of the Bromine 318 X3= 954


953 substance was estimated; the difference between these Iodine

9 Tellurium

473 X3=1419 numbers gives the heat absorbed in decomposing the compound; this difference is assumed to be equal to that evolved during its formation. Lewis Thomson's apparatus

The Spectrum of Didymium Nitrate.-Lawrence for determining the heating power of fuel was used. An Smith and Lecoq de Boisbaudran.-Didymium nitrate, oxidising mixture of 3 parts of potassium chlorate and if neutral or slightly acid, gives an absorption spectrum one of potassium nitrate was used, with some sulphur almost identical with that of the chloride ; the elementary added to promote combustion. The author discusses the probable errors of the estimation. The following table rays of the bands are less distin&. An addition of nitric

acid, however, produces certain important changes which gives the principal results obtained :

the authors describe.-Comptes Rendus,


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