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Chemical Discussion Association-Notices of Patents.

without much uniformity in the conclusions arrived at. From extensive researches made by American observers, Commander Maury had attempted to prove that near to each tropic there was the crest of a large atmospheric wave, from which air flowed down towards the equator on one side, and towards the pole on the other; and that light air ascended from the surface in both the polar regions. Numerous English registrations have been placed in the hands of Admiral Fitzroy, who has not like Commander Maury, promulgated a new hypothesis, but has exhibited what he considers the general action of cyclonic storms in middle latitudes; this is, however, opposed to the Hadleian theory. Sir J. F. Herschel, in his elaborate work "On Meteorology," omits to notice the disturbing influence of the liberated heat of condensing vapour on the gases; but he also abandons the old theory of winds, and attributes them to the action of aqueous vapour in a new form. It is contended by the writer, that the great cause of atmospheric disturbance is to be found in the local heating of gases by the liberated heat of condensing vapour. It is then pointed out that the term "atmospheric wave" is founded on a false analogy, and leads the mind in a wrong direction. To speak of storms coming from a certain quarter also misleads, as the cause of storms is to be found in the part towards which the wind blows. In conclusion it was suggested that aëronauts, when ascending into the higher regions to ascertain the state of the atmosphere in those regions, should, in addition to the ordinary instruments, use a wet bulb thermometer in conjunction with a dry one, in order that the hygrometrical state of the upper regions may be ascertained.1

CHEMICAL DISCUSSION ASSOCIATION.

THE following is the Report of the Fourth Anniversary
Meeting held on Monday, January 13, 1862, Dr. T.
REDWOOD, President, in the chair:-

The progress which has been made by the Chemical Discussion Association during the past year has been upon the whole satisfactory. The number of Members upon the list at the present time amounts to thirty-three. Of these six have been elected during the past year. In the case of five, however, their election took place during, or since October, and, therefore, in accordance with Rule IX. their subscriptions date for 1862.

At the previous Anniversary Meeting it was resolved to effect an alteration in Rule XI. by which greater facilities would be afforded to the Committee for removing members

in arrear.

That alteration has since received the necessary sanction of the Council of the Pharmaceutical Society, and the Committee have in accordance with the amended Rule removed the names of seven members who had expressed themselves unable to take any further active part in the Association.

Seven ordinary meetings have been held during the past year, and although the attendance has been rather below the average, the number of communications has been well maintained. Three of the communications have been already published in the Pharmaceutical Journal, and three or four others will probably also shortly appear. The following is the list of subjects which have been brought forward during the past year :

"On the Purification of Gum Resins," Mr. Allchin. "On some Fluid Preparations of Ipecacuanha," Mr. A. F. Haselden. "On the Iodide of Potassium and Compound Iodine Ointments," Mr. Hall. "On the Preparation of Smelling Salts," Mr. Allchin. "On the Ammonio Chrome Compounds," Mr. J. H. Baldock. "On some Reactions

1 Mr. Welsh employed the wet bulb thermometer in his balloon ascents. -Phil. Trans., 1853. Pt. 3.-ED.j

{CHEMICAL NEWS,

March 8, 1862.

"The Volatile

of Liquor Nasturtii," Mr. J. Schweitzer.
Portion of Sesquicarbonate of Ammonia," Mr. C. H.
Wood. "On the Action of Oxide of Silver on Creasote,"
Mr. Haselden. "On the Adulteration of Tin-Foil," Mr.
J. H. Baldock. "On a Cheap Form of Apparatus for
Spectrum Analysis," Mr. Alexander Waugh. "On the
Nutritive Value of Dika Bread," Mr. Attfield.
Remarks on the Efflorescences which form on Medicinal
Extracts," Mr. Attfield. "On the Detection of Alum in
Bread," Mr. C. H. Wood; and "On the Preparation
and Properties of Peroxide of Hydrogen," Mr. J. Robbins.

NOTICES OF PATENTS.

"Some

1144. Lubricating Compound. W. E. NEWTON, Chancery Lane, London. A Communication. Dated May 6,

1861.

THE patentee claims the use for lubricating purposes of various saponified combinations of fatty matters with the alkalies, potash and soda; and particularly specifies the animal fats, bees-wax, and the vegetable oils as being suitable for the preparation of such materials.

The potash and soda compounds here referred to are not in any respect different from the two ordinary qualities of soap, which have been so long and generally employed for cooling the surfaces of cutting implements, and for lubricating the bearings of machinery.

1149. Manufacture of Artificial Fuel. J. B. JARLOT, Port Mabon, France. Dated May 7, 1861.

THIS specification describes the mechanical details of improvements in the construction of cylindrical rollers for the purpose of better adapting them to the moulding of small coal in the manufacture of artificial fuel.

1166. Gutta Percha and Compounds thereof. J. R. HUNT, Chichester Place, Wandsworth Road. Dated May 8, 1861.

THESE Compounds are prepared by incorporating vulcanized India-rubber in a finely divided state with masticated gutta-percha in a doughy condition, employing the former in the proportion of about one-half by weight. In some cases it is considered desirable to mix in with the beforementioned compound a small quantity of arrow-root, four ounces of the latter is prescribed as being sufficient for three pounds weight of the compound of gutta percha and India-rubber. These materials require to be very thoroughly incorporated before being rolled into sheet.

The uncertainty regarding the durability of some kinds of gutta percha may often be traced to the employment of foreign substances, and especially to the admixture of those which do not really evince any property of uniting with the natural gum. Starch, in the form of arrowroot, must surely be considered one of that class which would be prejudicial to the quality of the gutta percha.

1177.

Decoloration and Disinfection of Liquids. J. H. JOHNSON, Lincoln's Inn Fields, London. Dated May 9, 1861. (Not proceeded with.)

THIS proposal refers to the employment alternately of chloride of lime and hydrochloric acid for the purpose of destroying the colour and objectionable odour of some kinds of oil. In applying this process the oil is introduced with a sufficient quantity of dry chloride of lime into a closed vessel fitted with a rotating vertical shaft provided with numerous inclined blades by which the oil is kept constantly agitated for the period of about half an hour; at the expiration of that time, the hydrochloric acid is admitted, and when the action of the chlorine is complete the oil is passed through fine strainers, and freely exposed to the oxidising influence of the air.

NEWS

1862.

1192. Treatment of India Rubber. P. A. GODEFROY, New North Road, Islington. Dated May 10, 1861. (Not proceeded with.)

In treating the India-rubber according to this invention the goods are to be immersed in a mixture of bisulphide of carbon and chloride of sulphur, removed from this solution, and dried by exposure to air. The rubber is next submitted to the action of Gallipoli oil to which sulphuric acid in the proportion of one-eighth has been previously added and intimately mixed by stirring. After remaining in this bath for about fifteen minutes it is taken out, rinsed in hot water, and placed in the boiler or steam chamber, where, according to the thickness of the rubber it is exposed to a temperature between the limits of 212° and 3c0° Fahrenheit, and left in the apparatus from one to four hours. The goods having undergone this process, are perfectly vulcanized and require only to be dried and

finished as usual.

The bisulphide of carbon and the chloride of sulphur are most convenient agents for effecting the vulcanization of India-rubber; the use of olive oil would, on the other hand, be likely to deteriorate the goods by penetrating the substance of the caoutchouc and giving rise to the formation of a soft, unctuous compound with surfaces of an adhesive

character.

243. George Phillips, sen., and George Phillips, jun., Holborn Hill, London, "Improvements in the distillation and rectification of alcohols or spirits."-Petition recorded January 28, 1862.

Chemical Notices from Foreign Sources.

I. MINERAL CHEMISTRY.

Chim. de Paris, No. 6, p. 112) is more easily prepared from Pyrophoric Iron.-M. Carlet says (Bull. de la Soc. calcined oxalate of the protoxide than from the sesquioxide ordinarily employed.

Action of Sodium Amalgam on Sulphide of Carbon.-M. Guignet (Ibid., p. 111) has observed that when an amalgam of sodium with an excess of mercury is left in contact with sulphide of carbon for several days, the amalgam breaks up into small granules, and the whole of the sodium is acted on. On adding water to the mixture, a very deep blood-red solution is obtained. An acid precipitates yellow flocculi from this, which dissolve again in sulphide of sodium, and reproduce the blood-red compound. The red body is also soluble in alcohol. M. Guignet found small quantities of mercury in the compound, but as it had not been purified by crystallization, he is unable to say whether the mercury is an essential or accidental constitutent of the salt.

Grants of Provisional Protection for Six Months. 3080. Mare Antoine François Mennons, Rue de l'Echi- Atomic Weight of Lithium.-Dr. Karl Diehl has quier, Paris, "A new or improved combination of micro-made in Bunsen's laboratory (Annal. der Chem. und Pharm. scopic photographs and lenses with certain precious stones Bd. cxxi. s. 93) fresh investigations to ascertain the atomic or imitations thereof."-A communication from Louis weight of lithium. He obtained the following results:— Henri Bouillette and Jean Amable Hyvelin, Rue Michel- 7023; 7·034; 7·012; 7'036; mean, 7'026. le-Comte, Paris.-Petitions recorded December 9, 1861.

113. William Cleland, St. George's Hill, Everton, Liverpool," Improvements in treating and utilising certain materials used and products obtained in the manufacture of gas, and in apparatus connected with the said treatment."-Petition recorded January 15, 1862.

123. Thomas Myers, Bloomsbury Square, London, and Edward Myers, Millbank Street, Westminster, "An improved composition for preventing rust on bright steel, iron, brass, or metal surfaces."

243. George Phillips, sen., and George Phillips, jun., Holborn Hill, London," Improvements in the distillation and rectification of alcohols or spirits."

275. Friedrich Wilhelm Daehne, Swansea, Glamorganshire, "Improvements in furnaces used in the manufacture of zinc."

303. John Browning, Minories, London, "Improvements

in aneroid barometers.'

"

305. Edward Harrison, Oldham, Lancashire, "A certain compound, or certain compounds, to be used as a substitute for gunpowder."

312. James Pitkin, Clerkenwell, London, "An improve

ment in aneroid barometers.'

320. John Tonkin, jun., Pool, Illogan, Cornwall, "Improvements in the manufacture of gunpowder."-Petitions recorded February 6, 1862.

Notices to Proceed.

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Double Salt of Iodate of Soda and Chloride of

Sodium.-Rammelsberg describes (Bericht der Akad. d. Wissenchaft zu Berlin, 1861, s. 893) crystals of a salt containing 2 (NaO, IO) + 3 (NaCi) + 18 aq. He had previously described a salt containing one atom of iodate of soda, two of chloride of sodium, and twelve of water; but he thinks this formula may not have been correct.

The Sulphates of Cadmium, Didymium, and Cerium Isomorphous.—According to Rammelsberg (Ibid. s. 891), the above salts constitute a new isomorphous group exactly analogous in composition and form. They all crystallize in the oblique prismatic system.

II. ORGANIC CHEMISTRY.

Todal.-M. Schoonbroodt (Bulletin de la Soc. Chim.de Paris, No. 6, p. 109,) formed a solution of hypochlorite of potash into an alcoholic solution of iodine until it was decolorized, and in that way obtained an abundant precipitate of white, silky flocculi, which he found to be soluble

in water.

The addition of a solution of potash to a solu

tion of the flocculi split up the compound into iodoform

and formic acid, so the author considers it iodal CHIO2. It does not, however, look very much like the body described under that name by Gmelin.

Test for Caffein.—Schwarzenbach gives the following (Chem. Centralblatt, No. 62, 1861,) test by which the caffein extracted from a single coffee bean may be recognised. The caffein is evaporated to dryness with some chlorine water, by which means a purple red residue is obtained. This, when strongly heated, changes to a golden yellow colour, but after cooling, ammonia will instantly restore the purple red.

Crystalline Structure of Wax.-According to Decjordin and Böttger (Neues Jahrb. für Prakt Pharm. Bd. cxvi. s. 309,) wax can be seen to assume a crystalline form in the following way: A piece of bees'-wax is placed in an evaporating dish three-quarters filled with distilled water; the vessel is heated until the wax is perfectly fluid, and is then removed from the fire to cool slowly. Any bubbles of air in the wax must be got rid of by stirring with a hot iron spatula, so that it may have a per

140

Miscellaneous-Answers to Correspondents.

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Use of Apples in Dyeing.-The following letter appears in the Journal of the Society of Arts: Sir, There has been an opinion prevalent, especially in the West of England, that apples have been extensively used in the application of some of the new and brilliant dyes mentioned by Dr. Crace Calvert; and I have found many well-informed men in the City, as well as the majority of the members of the Society of Arts to whom I have mentioned the subject, fully believe it. You will, perhaps, not think it out of place to allow the Journal to be the medium of giving the assertion a distinct denial. Dr. Calvert has allowed me to use his name in stating that it is a complete hoax; but, to show the utility of giving publicity to this statement, he told me the rumour has obtained such general currency, that he has been called on in Manchester by persons who have been thus misled, and have involved themselves in some expense to supply the market with malic acid from some cheaper source, as, of course, may be easily done; but they have found, to their disappointment, that there is no market for the article.

W. SYMONS."

new art.

Enamelling Iron.-Enamelling iron is almost a No metal is capable of receiving a coating of vitrified porcelain or enamel unless it is capable of withstanding a red heat in a furnace. Articles of cast iron, as a preparation for enamelling, are first heated to a low red heat in a furnace, with sand placed between them, and they are kept at this temperature for half-an-hour, after which they must be allowed to cool very slowly, so as to anneal them. They are then subjected to a scouring operation with sand in warm dilute sulphuric or muriatic acid, then washed and dried, when they are ready for the first coat of enamel. This is made with six parts, by weight, of flint glass broken in small pieces, three parts of borax, one of red lead, and one of the oxide of tin. These substances are first reduced to powder in a mortar, then subjected to a deep red heat for four hours in a crucible placed in a furnace, during which period they are frequently stirred, to mix them thoroughly; then toward the end of the heating operation the temperature is raised, so as to fuse them partially when they are removed in a pasty condition and plunged into cold water. The sudden cooling renders the mixture very brittle and easily reduced to powder, in which condition it is called frit. One part of this frit, by weight, is mixed with two parts of calcined bone dust, and ground together with water until it becomes so comminuted that no grit will be sensible to the touch when rubbed between the thumb and finger. It is then strained through a fine cloth, and should be about the consistency of cream. A suitable quantity of this semi-liquid is then poured with a spoon over the iron article, which should be warmed to be enamelled, or if there is a sufficient quantity the iron may be dipped into it and slightly stirred, to remove all air bubbles and permit the composition to adhere smoothly to the entire

CHEMICAL NEWS, March 8, 1862.

surface. The iron article thus treated is then allowed to stand until its coating is so dry that it will not drip off, when it is placed in a suitable oven, to be heated to 180 deg. Fah., where it is kept until all the moisture is driven off. This is the first coat; it must be carefully put on, and no bare spots must be left on it. When perfectly dry the articles so coated are placed on a tray separate from one another, and when the muffle in the furnace is raised to a red heat they are placed within it and subjected to a vitrifying temperature. The furnace used is similar to that used for baking porcelain. This furnace is open for inspection, and when the enamel coat is partially fused the articles are withdrawn and laid down upon a flat iron plate to cool, and thus they have obtained their first coat of dull, white enamel, called biscuit. When perfectly cool they are wetted with clean soft water, and a second coat applied like the first, but the composition is different, as it consists of thirty-two parts by weight of calcined bone, sixteen parts of China clay, and fourteen parts of feldspar. These are ground together, then made into a paste, with eight parts of carbonate of potash dissolved in water, and the whole fired together for three hours in a reverberating furnace; after which the compound thus obtained is reduced to frit, and mixed with sixteen parts flint glass, five and a-half of calcined bone, and three of calcined flint, and all ground to a creamy consistency, with water like the preparation for the first coat. The articles are treated and fired again, as has been described in the preparation coat, and after they come out of the furnace they resemble white earthenware. Having been twice coated, they now receive another coat and firing, to make them resemble porcelain. The composition for this purpose consists of four parts by weight of feldspar, four of clear sand, four of carbonate of potash, six of borax, and one each of These are oxide of tin, nitre, arsenic, and fine chalk. roasted and fritted as before described, and then sixteen parts of it are mixed with the second enamel composition described, excepting the sixteen parts of flint glass which is left out. The application and firing are performed as in the other two operations, but the heat of vitrification is elevated so as to fuse the third and second coats into one, which leaves a glazed surface, forming a beautiful white enamel. A fourth coat, similar to the third, may be put on if the enamel is not sufficiently thick. The articles may be ornamented like china ware, by painting coloured enamels on the last of the coats, and fusing them on in the furnace. A blue is formed by mixing the oxide of cobalt with the last named composition; the oxide of chromium forms a green, the peroxide of manganese makes a violet, a mixture of the protoxide of copper and red oxide of lead a red, the chloride of silver forms a yellow, and equal parts of the oxide of cobalt, manganese, and copper form a black enamel when fused. The oxide of copper for red enamel is prepared by boiling equal weights of sugar and acetate of copper in four parts of water. The precipitate which is formed after two hours' moderate boiling is a brilliant red. The addition of calcined borax renders all enamels more fusible.-Engineer.

ANSWERS TO CORRESPONDENTS.

Gun-Cotton.-J. S.-To make a highly-explosive and perfectly insoluble gun-cotton, mix together 10 fluid ounces of nitric acid, sp. gr. 16, and 13 fluid ounces of sulphuric acid, sp. gr. 184. Allow the mixture to cool, and immerse 400 or 500 grains of cotton in it for ten minutes. Wash as usual.

W. Kaye. We do not know the exact address. Somewhere in the United States.

H. S. R.-Soveral different products may be left behind on burning gunpowder,-such as sulphide of potassium, or sulphate of potash. We cannot say what the globules are without an examination.

A Constant Reader.-Naphthaline'and naphthalidine may be separated from benzol by distillation over a water bath. The benzol comes away, and leaves the other bodies, which do not distil except at a high temperature.

A Subscriber.-One shilling a month.

Books Received.-"On Pepsine." By M. Boudault. Translated by W. S. Squire, Ph.D., F.C.S. London: John Churchill.

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THE CHEMICAL NEWS.

VOL. V. No. 119.-March 15, 1862.

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THERE is another opportunity for an ingenious and enterprising Chemist. A Select Committee of the House of Commons is about to enquire into the possibility, or the best method, of utilising sewage. Whatever may be Mr. Brady's reason for moving for this Committee, it cannot be because the subject has hitherto received no attention. The Government referees on the Metropolitan Main Drainage Schemes, in 1857, went fully into the question. They employed Dr. Hofmann and the late Mr. Witt to make the necessary chemical investigations; and the elaborate report of these gentlemen constitutes a textbook of the chemistry of the subject. In the same year, Mr. Austin, one of the superintending Inspectors of the Board of Health, wrote a long report "On the Means of Deodorising and Utilising the Sewage of Towns." In the same year, too, Her Majesty, "reposing full trust and confidence" in several noblemen and gentlemen_well known in various capacities, constituted them a Royal Commission, and gave them" full power and authority" to investigate the same subject. But in this case Her Majesty's trust and confidence seem to have been a little misplaced; for, after a year's delay, the Commissioners issued a 66 Preliminary Report," telling us nothing but what was well known before, and since then have been silent-the "Preliminary Report" apparently being a final one.

During the same time, the private investigators and speculators on the subject have been numerous. Many patents have been taken out for treating sewage in a variety of ways to make valuable manures; and the persevering Mr. Mechi and others have laboured hard to bring about the general adoption of a scheme for flooding the country with liquid sewage. But few, however, of these schemes are tried, or, if they are, they do not often pay. On a small scale, the irrigation plan has been found to answer. But the sewage of Edinburgh is too much for the meadows around that city, and whenever it rains -and it often rains in Edinburgh-the sewage is sent into the sea. What, then, can be done with the 100 millions of gallons which flow daily through the London sewers enough almost to fertilise the Desert of Sahara? It is the quantity with which our ingenious and enterprising chemist has to deal, that constitutes his great difficulty. True, if the valuable part were solid, there would be no great difficulty in filtering 100 millions of gallons, and saving the solid portion. But, unfortunately, six-sevenths of what is worth anything in sewage exists there in solution, and how shall 100 millions of gallons be evaporated every day? The lime process is said to be the best of the precipitation plans, but nobody will buy the manure produced in that way, even when made conveniently in the centre of a large agricultural district, as at Leicester; and how could it possibly be got rid of in London, produced at the rate of more than 2000 tons a-day?

We need not now speak of the charcoal and other plans for clarifying and filtering sewage, nor of Sir James Murray's process for (according to Hofmann and Witt) obtaining four pennyworth of ammonio-magnesian phosphate by materials costing 3s. 2d. It is enough that we call the attention of chemists to the present opportunity, and invite them to discuss the subject. Perhaps some one of our readers carries locked up in his bosom the secret of a cheap and effectual precipitant of ammonia and phosphoric acid in very dilute solution. If so, now is his time. Mr. Brady's Committee will make his fame and fortune, and we recommend him to send in his name without delay.

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Rosaniline.-The most available substance for the extraction of this base is the acetate, which is generally employed in dyeing, and which Mr. Nicholson prepares perfectly pure. The boiling solution of this salt, decomposed by a large excess of ammonia, yields a crystalline precipitate of a reddish colour, which consists of the base, in a state of great purity.

line.

The colourless liquid separated by filtration from the precipitate, deposits on cooling perfectly white needles and crystalline tablets. This is absolutely pure rosaniUnfortunately, the solubility of the base in ammonia, or even in boiling water, is extremely slight, so that a very small quantity only of this compound is obtained in an absolutely pure condition.

Rosaniline is a little more soluble in alcohol; the liquid possesses a deep red colour; it is insoluble in ether. Exposed to the action of the atmosphere, the base rapidly becomes rose colour, and ends by taking a deep red tint. During this change of colour no sensible variation of weight is observable. At the temperature of 100° C., rosaniline loses a small quantity of adherent water; it can then be heated to 130° without change of weight; at a higher temperature rosaniline decomposes, disengaging an oily liquid consisting chiefly of aniline, and leaving a black carbonaceous residue.

A combustion of rosaniline led to the formula:C20H21N3O=C20H19N3, H2O, which was corroborated by an examination of several salts and characteristic derivatives.

Rosaniline is a powerful and well-defined base, forming several series of salts, almost all remarkable for their facility of crystallisation. The proportions in which this substance unites to acids assign to it the characters of a tri-acid triamine. Like many other triamines which I have examined, it appears capable of producing three classes of salts.

142

On the Colouring Matters Derived from Aniline.

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At present, however, I have only succeeded in forming
the representatives of the first and the third class. The
tendencies of rosaniline are essentially mono-acid. The
salts with one equivalent of acid are extremely stable
compounds. I have crystallised them four or five times
without altering them in the slightest degree.
The salts
with three equivalents of acid possess only a compara-
tively slight stability, being decomposed by the action of
water, or by an exposure to a temperature of 100°.

On glancing at the above formulæ, it is evident that the white crystals of the base itself constitute a hydrate; the saline compounds of rosaniline, as may be seen on considering several of the processes giving birth to this base, do not contain oxygen. The salts of rosaniline may be obtained by two different processes, either by the direct action of the several acids, or by submitting the ammoniacal compounds of these acids to ebullition in the presence of an excess of the free base. These two methods furnish the salts equally pure and of the same composition.

CHEMICAL NEWS,
March 15, 1862.

The

kept at this temperature until their weight becomes
constant, the original green salt, with one equivalent of
acid, is re-produced, as has been proved upon analysis.
Possibly the blue coloration indicates the ephemeral
formation of an intermediate di-acid compound.
two chlorides combine with bichloride of platinum. The
compounds so produced being uncrystallisable, are not
easily obtained in a state of purity. From the deter-
mination of the platinum, which has only given approxi
mate results, I ascribe to these salts respectively the
following compositions:-

C20H19N3, HC,PtCl2,
C20H19N3,3 HCl, 3PtCl2.

Bromide of Rosaniline resembles in every respect the chloride. It is still less soluble than the latter. Dried at 130°, the salt contains

C20H19N3,HBr.

Sulphate of Rosaniline is easily obtained by dissolving the free base in dilute boiling sulphuric acid. Upon cooling, the salt is deposited in green crystals, with a metallic reflection, which are rendered quite pure by one crystallisation. It is difficultly soluble in water, more so in alcohol, and insoluble in ether. At 130°, a temperature at which it loses a small quantity of water, the composition of this salt is, C20H19N3H SO.. C20H1N,H

The salts with one equivalent of acid for the most part present in reflected light the green metallic aspect of cantharides' wings. Seen by transmitted light, the crystals are red, becoming opaque when they are of any thickness. The solutions of these salts in water or alcohol possess the magnificent crimson colour The acid sulphate crystallises difficultly. I have not for which this substance is famous. The salts with analysed it. three equivalents of acid, are, on the contrary, of a Oxalate of Rosaniline. The preparation and proyellowish brown, both in the solid state and in solution.perties of this salt are quite similar to those of the They are much more soluble in water and alcohol than sulphate. The salt retains at 100° one equivalent of the mono-acid salts, which for the most part are compa- water, and at this temperature is represented by the ratively slightly soluble. The two classes of salts of formula, rosaniline crystallise easily, especially the mono-acid compounds. Mr. Nicholson has obtained several of them in perfectly defined crystals, which are at present in the hands of M. Quintino Sella, to be examined crystallographically.

Chlorides. ---These compounds, and especially the mono-acid salts, have particularly served to determine the formula of rosaniline. Prepared either by the action of hydrochloric acid, or by means of chloride of ammo nium, this salt deposits from its boiling solution in welldefined rhombic tables, often united together in the form of a star. The chloride is difficultly soluble in water,

more soluble in alcohol, and insoluble in ether. This salts retains a small quantity of water at 100°, but becomes anhydrous at 130°. At this temperature it contains,

C20H19N3,HC1.

!

Like most salts of rosaniline, it is very hygroscopic, a character which must not be lost sight of in analyses of these compounds. The mono-acid chloride dissolves more easily in moderately-diluted hydrochloric acid than in water. If the slightly warm solution is mixed with very strong hydrochloric acid, it solidifies on cooling to a mass of magnificent needle-shaped crystals of a reddish brown colour, which must be washed with concentrated hydrochloric acid and dried in vacuo over sulphuric acid and lime. Water decomposes them, reproducing the mono-acid compound. The salt obtained by the action of concentrated hydrochloric acid is the compound, with three equivalents of acid,

C20H19N3,3HC1.

Heated to 100°, this salt gradually loses its acid; the brown crystals become of an indigo-blue colour, and if

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The water may perhaps be removed at a higher tem perature, but the temperature at which it is expelled and

that at which the oxalate commences to decompose are so near to one another that it is not very easy to obtain the salt in the anhydrous state. I have not succeeded in preparing an oxalate containing a larger proportion of acid.

Acetate of Rosaniline.—This salt is probably the most beautiful of the series. Mr. Nicholson has obtained it in crystals a quarter of an inch thick, which, submitted to analysis, have proved to be the mono acid acetate in a state of purity,

C20H19N3, HC2H2O2.

The acetate is one of the salts most soluble in water and alcohol. It cannot be readily re-crystallised.

Formiate of Rosaniline is similar to the acetate. Amongst the other salts which this base forms I may mention the chromate, which is obtained by the addition of bichromate of potash to the solution of the acetate, in the form of a brick red precipitate, changing by the action of water to a crystalline green powder, almost insoluble. The picrate ought also to be mentioned. It crystallises in magnificent red crystals, likewise very difficultly soluble in water.

(To be continued.)

A Convenient Apparatus for the Estimation of Carbonic
Acid, by EMERSON J. REYNOLDS.
THE little apparatus which it is my object in the present
paper to describe, is one that I have continually used for

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