cury actuates, by means of a relay, a secondary current superimposed upon the primary heating current. Various modifications of the method are suggested, and it is stated that its use will render possible the maintenance of temperatures up to 1500° C.

M. CHARLES FÉRY contributed to the Discussion a short Note on "Stellar Pyrometry."

The temperatures of incandescent terrestrial bodies can be measured by reference to the laws of radiation, either the law of Stefan or the law of monochromatic radiations, but these cannot be applied in the case of stars, owing to the small amount of radiation. The author has therefore devised an instrument based on Weiss's displacement law, according to which temperature is measured by an appreciation of the colour tint of the star. In the instrument described the colour of an image of the star is compared with that of a standard lamp whose tint can be varied. The pyrometer is standardised by reference to an electric furnace, an arc (3500° C.) and the sun (6500° C.).

In the course of the general discussion which followed the reading of the papers

Dr. T. M. LOWRY suggested the use of helium or argon in high-temperature gas thermometers instead of nitrogen. Dr. J. A. HARKER agreed that a substitute would have to be found for nitrogen, which was not inactive in the electric furnace. Helium was impracticable, but he thought argon promising. The difficulty was a suitable containing material; they were trying to find one at the National Physical Laboratory.

Dr. ARTHUR DAY threw out the suggestion that tungsten might be found a possible material.

Prof. A. K. HUNTINGTON commented on the distinction which should be drawn between the diffusion of gases through metals, which depended on affinity, and through porcelain, which was merely a matter of porosity.

NOTICES OF BOOKS.

Physico-chemical Tables. Vol. II. By JOHN CASTELLÉVANS, F.I.C., F.C.S. London: Charles Griffin and Co., Ltd. 1911. (36s. net).

THE second volume of this comprehensive book of physicochemical tables contains many lists of data relating to capillarity, surface tension, the physical properties of solutions, and molecular weights. Analytical tables are also included, and very full lists are given of multiplying factors and logarithms for every substance which is likely to be met with in analytical work. Methods of calculation and the use of the tables are fully explained, and it would be a difficult matter to suggest additions or improvements to make the book more complete or convenient in use.

Crystals. By A. E. H. TUTTON, D.Sc., M.A., F.R.S. London: Kegan Paul, Trench, Trübner, and Co., Ltd. 1911. (58.).

THIS book is an amplification of the author's Evening Discourse to the British Association at the Winnipeg Meeting held in 1909, and gives a full account of the advances which have recently been made in crystallography. The experiments which were performed at the lecture are described in detail, and the phenomena exhibited by crystals in polarised light are admirably shown in the illustrations. The subject is treated as simply as is compatible with a thorough exposition of its essential features, and technical and mathematical terms are avoided as far as possible. The author's enthusiasm for his subject will inevitably awaken his readers' interest, and his accounts of the early study of crystals, of the work of Mitscherlich, and of liquid crystals are most stimulating. The growth of a crystal from a solvent, and the parallelism of crystal growth and the growth of a living organism is treated in a really fascinating style, the salient points being made exceedingly clear,

By

The Manufacture of Sulphuric Acid and Alkali. GEORGE LUNGE, Ph.D. Third Edition. Volume III. London Gurney and Jackson. 1911. (30s. net). THE third volume of the third edition of this treatise deal s with the ammonia-soda process and the chlorine industry, as well as various suggested methods for manufacturing alkali which the author criticises from the point of view of their practicability. Throughout the book the reader meets with shrewd comments upon the usefulness of the different processes reported upon, and the author, keeping in view his special aim of comprehensiveness, has not hesitated to describe in detail a proposed method and then explain the inherent defects which would prohibit its successful adoption. Even obsolete methods which are of historical interest only are included, and much of Prof. Lunge's recent work is discussed.

Inorganic Chemistry. By F. STANLEY KIPPING, Ph.D.,
Sc.D., F.R.S., and W. H. PERKIN, Ph.D., Sc.D., LI.D.,
F.R.S. London and Edinburgh: W. and R. Chambers,
Ltd.
1911. (7s. 6d.).

THIS text-book of inorganic chemistry, the first part of which has already been reviewed in these columns, provides a continuous three years' course, suitable for students who are beginning the study of the science, and who aim at obtaining a University pass degree. In Part I. the first year's course is given, the chapters being arranged in the order in which the author believes the subject can most profitably be studied, and in the second part the more detailed study of the elements grouped according to the Periodic System is taken up. Throughout the book much space is given to the consideration of the principles and theories of chemistry, and the discussions of theory are exceedingly clear and concise, giving precisely what the average student requires for a proper understanding of the fundamental laws of the science. The theoretical matter includes practically all that can be profitably studied before advanced work is taken up, and the book would want but very little supplementing on this side, though the treatment might be found rather slight from the point of view of descriptive chemistry. An attempt has been made to differentiate between the second and third year's work by running a line down the margin of the more advanced matter, which, however, takes its proper place in the text, so that there is no disturbance of the continuity. The book is one which is likely to be widely adopted, and only a very cursory survey will be necessary to convince both teachers and learners of its merits, which will be made still more conspicuous by constant use.

Die Chemie der Cellulose. ("The Chemistry of Cellulose"). By SCHWALBE. Volume I. Berlin: Gebrüder Borntraeger. 1911. (9 mk. 60 pfg.).

THIS treatise contains a complete summary of all the facts which are known concerning the chemistry of cellulose. Cotton cellulose, as being the most thoroughly studied representative of the class, is considered first, and Part I. of Vol. I. gives an account of its preparation in the pure state and its behaviour towards reagents, including dyes. Among the reagents taken into account are water, acids, alkalis, and oxidising agents, and the effects of heating, of air and light, as well as the results of passing an electric current through suspensions of cellulose, and the fermentation of the substance are all described. The second part of the book deals with the derivatives of cellulose, e.g., its hydrates and oxy-derivatives. Some of the author's as yet unpublished results are included, and very full references are given to the literature of the subject. The book prepares the way for further advances in the scientific knowledge of cellulose, especially as regards its investigation from the point of view of colloid chemistry, from which many important results may be expected.

on

CHEMICAL NEWS, July 7, 1911 Themen der Physikalischen Chemie. ("Essays Physical Chemistry "). By Dr. EMIL BAUR. Leipzig: Akademische Verlagsgesellschaft. 1910. (4 marks). THESE essays are based upon lectures which were delivered at the vacation courses for engineers held at the Technische Hochschule at Brunswick, and which were evidently ercellently suited for their purpose. They gave in an interesting and succinct form a'r sume of the results which are the outcome of recent work on the different branches of physical chemistry. No special knowledge of chemistry would be necessary to follow the outlines of modern developments of catalysis, metallography, colloidal chemistry, to mention some of the subjects of the essays, and the fact that the lectures were illustrated by experiments must have added considerably to the interest of the audience and the benefit they derived. Every engineer who can understand German will find that he will gain some new points of view by reading the book.

ii

It

is not attacked by bromine, but in sunlight hydrobromic acid is set free and cyclohexyl bromide is formed. gives with bromine a viscous liquid from which no definite compound can be extracted. Dibromocyclohexane and methylcyclohexene are transformed by bromine in presence of aluminium almost quantitatively into hexabrombenzene, C6B16. Methylcyclohexane and 1-2 and 1-4-methylcyclohexene give a viscous liquid, and a solid product which consists chiefly of pentabromtoluene. 1-3-Dimethylcyclohexane gives tetrabromxylene, and from menthene and thymomenthene only viscous liquids are obtained. Dinaphthothiophene.-M. Lanfry.- When sulphur acts on naphthalene at a red heat a crystalline substance of formula C20H12S is obtained. On oxidation with acetochromic solution it gives o-phthallic acid. With bromine it yields a hexabromo derivative, and with boiling nitric acid a tetranitro compound, C20H8(NO2)4S, is formed.

Researches on Oxy-indazols. - P. Freundler.—At a low temperature the ortho-substituted azo-acids give chlorinated oxy-indazols with phosphorus pentachloride.

SOURCES.

hydroxyl group attached to the central carbon, The two chlorine atoms of the nucleus are in the 3 and 5 positions. The OH group confers on the oxyindazols a phenolic by the ease with which they can be converted into the corresponding azo-acids.

Comptes Rendus Hebdomadaires des Séances de l'Academie

des Sciences. Vol. clii., No. 19, May 8, 1911. Hydrates of Rubidium and Cæsium Fluorides.

M. de Forcrand.The following hydrates of rubidium and cæsium fluorides exist :-RbF+ 1.5H20 (m. p. 36°), RbF+H2O, CsF+1.5H2O, CsF+H2O. The dissociation temperatures are 256°, 178°, 260°, 182°.

Catalytic Decomposition of Formic Acid.-Paul Sabatier and A. Mailhe.-With dehydrogenating catalysers, such as platinum sponge, reduced copper, or zinc oxide, formic acid is decomposed according to the equation HCO2H = CO2 + H2. Dehydrating catalysers, such as TiO2, induce the following reaction: HCO2H CO+H2O, while with mixed catalysers, such as thorium dioxide, the action is 2HCO2H = HCOH + CO2 + H2O.

Production of Ammonia and Economy of Nitrogen by Peat.-H. Woltereck.-The author treated peat with water vapour alone, and after the formation of ammonia was completed, and the amount of nitrogen had been determined, subjected the residue to the action of a mixture of air and water. Thus it was found that treatment with water alone produced only one-third of the amount of ammonia obtained by the action of a mixture of water and air in the same conditions. Moreover, the amount of nitrogen lost in the action of the vapour corresponded nearly to that recovered in the form of ammonia. No acetic acid is formed by treatment with water alone at 450°, while in presence of air at the same temperature 2.31 per cent of acetic acid is obtained.

Gases contained in Steel.-G. Charpy and S. Bonnerot. - When the gases contained in steel are separated by heating in a vacuum at 950°, it is found that the small amount of water introduced owing to the use of a mercury air-pump and porcelain tubes brings about a reaction with the steel. The volume of gas obtained differs in different specimens of steel, the percentage of carbon monoxide varying from 26 to 32 per cent.

Action of Carbon Oxychloride on Natural and Artificial Sulphides.-Ed. Chauvenet.-At comparatively low temperatures (300-450°) carbon oxychloride acts on natural and artificial sulphides, giving chlorides, MS+COC12= MC12+ COS. Thus carbon oxychloride can be used to transform sulphides completely into anhydrous chlorides, and a method of opening up and determining natural sulphides can be based upon this process.

Bromination of some Hydroaromatic Derivatives. -F. Bodroux and F. Taboury. In the dark cyclohexane

Berichte der Deutschen Chemischen Gesellschaft.
Vol. xliii., No. 7, 1911.

Root-dye of Azafran.-C. Liebermann.-The author has investigated the dye which can be isolated from the root of a plant belonging to the Scrophulariaceæ and indigenous to Paraguay. The dye is obtained from the roots by means of boiling alcohol or benzene, when it separates in the form of orange-red flakes which melt at 214°. It is soluble in organic solvents, insoluble in water, When unaltered by alkalis and ammonia in the cold. boiled with alkalis or alkaline carbonates it dissolves, giving a yellow solution, from which it is re-precipitated by alkalis. With concentrated sulphuric acid it gives a blue colouration, which changes to violet on the addition of alcohol. The dye, for which the author suggests the name azafrin, contains no nitrogen. On analysis it is found to contain about 75 per cent carbon and 9 per cent hydrogenNo methoxyl or ethoxyl groups are present in it. Its molecular weight lies between 448 and 462, and it contains one hydroxyl group.

Atti della Reale Accademia dei Lincei.
Vol. xx., No. 5, 1911.

Nitropyrrol.-A. Angeli and Luigi Alessandri.-Pyrrol and its derivatives are decomposed by the action of nitric acid, but nitropyrrol can be prepared by adding an atom of sodium and a molecule of ethyl nitrate to a molecule of pyrrol diluted with ether. Thus the sodium salt of nitropyrrol and sodium nitrite are formed, and may be separated by adding a solution of silver nitrate; the silver salt of nitropyrrol, which is thus prepared, together with silver nitrite, is insoluble in water, while silver nitrite is soluble. The silver salt is converted into the sodium salt by the

Decacyclene and its Action on Graphite.-M. Padoa. -Decacyclene can be prepared by heating acenaphthene with sulphur, adding sulphuretted hydrogen, again heating to 250°, and then re-crystallising from nitrobenzene. When graphite was heated with pure decacyclene at 430° a fusion curve was obtained, exactly like that of pure decacyclene, and the graphite remained quite unaltered.

Vol. xx., No. 6.

Silicon Sulphides.-Livio Cambi.-Silicon monosulphide exists in two forms, one orange-yellow and the other black. When the former is hydrolysed the following reaction Occurs — - SiS 2H2O = H.SiO.OH + H2S. The black monosulphide undergoes dissociation, giving the disulphide 2SIS Si+SiS2. This recalls the behaviour of stannous sulphide from which tin and stannic sulphide are formed. Amorphous Silicon. - Livio Cambi. - The silicon obtained by the dissociation of the black sulphide of silicon may be regarded as amorphous silicon. It differs from the products described by Vigouroux, Hempel, and v. Haasey in physical properties, e.g., in colour and specific gravity. It turns brown when heated.

Luminosity of Phosphorus.-L. Marino and C. Porlezza. The authors describe an apparatus by means of which the luminosity of phosphorus can easily be demonstrated to a large audience. The hot vapour is carried into a large flask by a current of carbon dioxide, and then | appears to generate a beautiful green flame. It is found that when phosphorus is oxidised in oxygen, much diluted with an inert gas, the product is one of the lower oxides, probably P40. In excess of oxygen P2O5 is formed by the complete combustion of phosphorus, while, when phosphorus is heated in a current of air, P2O3 and P40 are formed. Existence of New Type of Dioxide.-L. Marino and V. Squintani. When 25 grms. of manganese dioxide are heated to 140° in a closed tube with 70 grms. of selenious anhydride dissolved in 500 grms. of water, a selenite of the dioxide is formed. The compound is orange-yellow coloured, insoluble in water, nitric acid, and dilute sulphuric acid. It is soluble in hydrochloric acid. It liberates iodine from a solution of potassium iodide acidified with acetic acid. With alkaline carbonates and hydroxides, MnO2 is set free, the decomposition taking place according to the equation MnSe206 → SeO2+2SeO2. When heated to 400° at atmospheric pressure the salt decomposes as follows: MnSe206 MnO2 + MnSe04. The ganous selenate gradually decomposes as the temperature is raised, the whole reaction being represented by the equation 5MnSe206→ 8SeO2 + 2MnSO4 + Mn304+02. All these results show that the compound MnSe206 is to be regarded as a selenite of manganese dioxide.

man

Thermic Analysis of Mixtures of Copper Chloride with the Chlorides of Monovalent Elements.-C. Sandonnini.-The crystallisation curves of mixtures of sodium chloride and copper chloride show a eutectic at 75 mol. per cent CuCl. In the system AgCl-CuCl, the eutectic occurs at 54'6 mol. per cent CuCl, and with KCl—CuCl at 67 mol. per cent CuCl. Thallium chloride gives a compound CuCl.2TICI, the temperature of forma tion being 226°. With potassium chloride also a double salt, CuCl.2KCl, is formed.

Binary Systems of Chlorides of Monovalent Metals. -G. Poma and G. Gabbi.- In this paper the authors give the results of the investigation of the systems CuCl-AgCl and CuCl-KCI, with graphic representations of the fusion curves.

Equilibrium of Solutions of Iodine in Organic Substances.-F. Olivari.-The solubility curve of iodine in the neighbourhood of the melting point of the element is practically the same for iodoform, azobenzene, p-dibrombenzene, and p-dinitrobenzene, while the slope of the

MISCELLANEOUS.

Royal Society of Arts.-The Annual General Meeting of the Royal Society of Arts took place on June 28th, Sir John Cameron Lamb, C.B., C.M.G., Chairman of the Council, presiding. The Annual Report shows that the office of President has now been accepted by H.R.H. the Duke of Connaught. Up to the death of King Edward VII. it was occupied by H.R.H. the Prince of Wales (King George V.), and, on his accession to the throne, it was temporarily held by the Lord Chief Justice. During the year twenty-two papers were read at the Ordinary Meetings of the Society, six in the Indian, and five in the Colonial Section. The has been, as usual, an increase in the entries for the Society's Examination, the total number of papers worked year being 34,260. The Society's Albert Medal has been awarded to the Hon. Sir Charles A. Parsons, K.C.B., F.R.S., for his experi. mental researches into the laws governing the efficient action of steam in engines of the turbine type. The Council, with a few alterations, was re-elected.

this

Royal Society of Arts' Medals.-The Council of the
Royal Society of Arts have awarded Silver Medals for
papers read during the past Session as follows:-
At the Ordinary Meetings.-
Campbell P. Ogilvie, "Argentina."
Vaughan Cornish, D.Sc., F.G.S., F.C.S., "The Panama
Canal."

Reginald A. Smith, B.A., F.S.A., "Roman London."
Philip Joseph Hartog, M.A., B.Sc., "Examinations."
George A. Stephen, "Bookbinding."
Dr. Leonard Hill, F.R.S., "Caisson Sickness and Com-
pressed Air."

James Cantlie, M,A,, M.B., C.M., F.R.C.S., D.P.H.,
George B. Heming, "Art Education in Jewellery, &c."
"Plague."
Prof. Raoul Pictet, "Les Basses Températures."
Frank M. Andrews, "Architecture in America."
Robert Fellowes Chisholm, F.R.I.B.A., F.S.A., "The
Taj Mahal."

In the Indian Section.

"Education in India."

Reginald Murray, "Banking in India."
Claude Hamilton Archer Hill, I.C.S., C.S.I., C.I.E.,
Sir Thomas Henry Holland, K.C.I.E., D.Sc., F.R.S.,
"Mineral Development in India."

W. R. H. Merk, I.C.S., C.S.I., LL.D., "The North-
West Frontier Province."

In the Colonial Section.

A. Montgomery, M.A., F.G.S., "

F.

Australia."

Mining in Western

Douglas Osborne, M. Inst. M.M., "The Tin Resources of the Empire."

Captain R. Muirhead Collins, R.N., C.M.G., "The F. Williams Taylor, "Canadian Banking."

Commonwealth of Australia."

NOTES AND QUERIES.

Our Notes and Queries column was opened for the purpose of giving and obtaining information likely to be of use to our readers generally. We cannot undertake to let this column be the means of transmitting merely private information, or such trade notices as should legitimately come in the advertisement columns.

lowing order of the succession of colours, or of any succession of Northern Lights.-Can any reader give an explanation of the folcolours, in what I have usually considered the "northern lights." The colours are golden tint from clouds, blue changing to dark blue, followed by red coloration chiefly from clouds. I have noted these appearances in various parts of England whilst Aurora or rather "northern lights" have been announced in the press.-J. C. T.

Cloth, 3/6 Paper covers, 216. (Postage, 4d. extra).

THE WHEAT PROBLEM:

Based on Remarks made in the Presidential Address to the British Association at Bristol in 1898.

REVISED WITH AN ANSWER TO VARIOUS CRITICS

By SIR WILLIAM CROOKES, F.R.S.
SECOND EDITION.

VITH PREFACE AND ADDITIONAL CHAPTER, BRINGING THE
STATISTICAL INFORMATION UP 10 DATE.

With Two Chapters on the Future Wheat Supply of the
United States, by MR. C. WOOD DAVIS, of Peotone,
Kansas, and the HON. JOHN HYDE, Chief Statistician
to the Department of Agriculture, Washington.

OPINIONS of the PRESS.

"Sir William Crookes's statistics seem to make good his alarmist statement."- British Weekly.

"Sir William Crookes has propounded a problem which in the next century [written in 1899] is bound to engage the close attention not merely of agricultural experts, but of economists and statesmen."-Speaker. "The appearance of the papers in this convenient form will be welcome to everyone who appreciates the importance of the problem."-Scotsman.

"The student of economic science and sociology will find this volume full of interesting material. . . The entire subject is of the profoundest interest, and an excellent purpose has been served by the publication of these papers in a single volume."-The Eagle (Brooklyn, N.Y.).

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