February 20, 1908J 



NA rURE 



Chemical Society, Fehtuiry 6.— Sir William Ramsay, 

 K.C.B., F.R.S., pr,-si(l.ni, in cIil- cliair.— The metallic 

 picrates : O. Silberrad and 11. A. i?hillips. The water 

 of crystallisation and properties of the commoner picrates 

 have been definitely established. — Some physicochemical 

 properties of mixtures of pyridine and water : H. Hartley, 

 N-. G. Thomas, and M. P. Applebey. — The constitution 

 of umbeihilone, part iii. : !•". Tutin, A refutation of 

 .SemnilerV recent statements [Bcr., 1907, .\l., 5017) re- 

 specting the constitution of umbellulone. — Colour and 

 constitution of azomethine compounds, part i. ; F. G. 

 Pope. The nitrohydro.xyazomethine compounds show an 

 entirely different absorption spectrum from that of their 

 alkali salts when the nitro- and hydroxyl groups are in 

 the para position to the azomethine group, and from the 

 similarity of the .N : CH. grouping to the .N : N. group- 

 ing it would seem that the alkali salts of these compounds 

 could be formulated on a di-quinonoid basis, the free 

 hydroxyl compounds being represented thus : — 



\\o( \v 



ind the alkali salts as 



N:CH; 



O; 



\= 



■:N. CII;/ ^:NO„K 



(compare Hewitt and .Mitchell, Trans., 1907, xci., 1251). 

 — The preparation of /-benzoin: .A. McKenxie and H. 

 Wren. — Organic derivatives of silicon, part v., bcnzvl- 

 ethylsilicone, dibenzylsilicone, and other benzyl and benzvl- 

 I thyl derivatives of silicane : R. Robison and F. S. 

 Kipping. Descriptions of these silicon derivatives are 

 givc-n. — The residual affinity of the coumarins and thio- 

 coumarins, as shown by their additive compounds : .\. 

 Clayton. The coumarins and thiocoumarins combine with 

 mercuric chloride, forming compounds of the tvpe 

 R.HgC'f., where R is a coumarin or a thiocoumarin. — The 

 influence of foreign substances on certain transition 

 temperatures, and the determination of molecular weights : 

 H. M. Dawson and C. ('■. Jackson. The changes in- 

 vestigated were : — - 



(i) Na,S,0„5H,O^^Na.S.O„2H,0 at j,%°-i ; 



(2) NaBr,2H,0— NaBr at so°-67'; and 



(3) CaCl„6H;0-l-2MgCL,6H„0— CaCI,,2.MgCI,,i2H,0 



at 22°-4. 

 Constants representing the depression of the transition 

 temperature when one gram-molecule of the foreign sub- 

 stance is contained in 100 grams of the saturated transition 

 solution have been calculated. From a knowledge of thesi- 

 constants, the corresponding invariant points mav be 

 utilised for the purpose of obtaining the molecular weights 

 of dissolved substances. — The bromination of /)-hydroxy- 

 diphenylamine : Miss \. E. Smith and K. J. P. Orton. 

 — The decomposition of animonium dichromate by heat : 

 \V. M. Hooton. If the salt is decomposed slowly by heal, 

 the final product is hydrated chromium dioxide, 

 2CrO,,H;0, a glistening black powder which when heated 

 yields oxygen, water, and chromium sesquioxide. If 

 ammonium dichromate is heated in absence of oxygen, the 

 final product is a dull, greenish-black powder having the 

 composition H,Cr,0,. — The effect of constitution on the 

 rotatory power of optically active nitrogen compounds, 

 part ii. : H. O. Jones and J. R. Hill. — Malacone, a 

 silicate of zirconium : .\. C. Cumminfr. The author finds 

 that the formula ZrO,,SiO. corresponds more closely with 

 the observed composition of malacone than does the 

 formula 3ZrO,,2SiO, assigned to it by Kitchin and 

 Wintersoii {Trans. Chem. Soc, 1906, Ixxxix., 1568). — 

 The reducibility of magnesium oxide bv carbon : R. E. 

 Slade. The isolation of magnesium by direct reduction 

 of the oxide by carbon has been effected at temperatures 

 above 1700°. Rapid evacuation of the vessel in which the 

 reaction occurs, absorption of the magnesium by molten 

 copper, and reduction of magnesia in presence of 

 aluminium or in a swift stream of hydrogen have all 

 proved useful in preventing the reverse reaction, which 

 occurs between magnesium and carbon mono.xide. — The 

 crystal form of halogen derivatives of open chain hydro- 

 ■ carbons with reference to the Barlow-Pope theory of struc- 

 ture : F. M. Jaegrer. In accordance with the theory of 

 Barlow and Pope, it is found that tetrabromo-SiS-dimethyl- 



NO. 1990, VOL, 77I 



propane, 1:3: 5^hexatriene, di- and tetra-bromide, and 

 tetraiodoethylene exhibit a close morphotropic relationship. 

 — The determination of the rate of change by measurement 

 of the gases evolved : F. E. E. Lamplough. — The 

 temperatures of spontaneous crystallisation of mixed solu- 

 tions, and their determination by means of the index of 

 refraction. Mixtures of solutions of sodium nitrate and 

 lead nitrate : Miss F. Isaac. — Contributions to the chem- 

 istry of the terpenes, part iii. ; some oxidation products of 

 pinrne : G. G, Henderson and I. M. Heilbron. — A 

 6-lactonIc acid from acetone and malonic acid : .-K. N. 

 Meldrum. When malonic acid and acetone are mix€d 

 with acetic anhydride and a little sulphuric acid, the 

 /3-lactone of )3-hydroxy!Sopropylmalonic acid, 

 CMe.,. Ctl. CO„lI 



I 

 -CO 



formed. 



P,\RIS. 



Academy of Sciences, February 10 — M. II. Becquerel 

 in the rhair. — The spectra of non-dissociated compounds : 

 Henri Becquerel. -A reply to a recent note of M. k. 

 Dufour, and pointing out the connection between the 

 results of M. Dufour and certain phosphorescent and 

 absorption spectra. — The alcoholysis of linseed oil : .A. 

 Hailer. The author has applied his method of saponifi- 

 cation with alcoholic hydrochloric acid to the preparation 

 of the methyl esters of the fatty acids contained in linseed 

 oil. These methyl esters were submitted to fractional dis- 

 tillation under reduced pressure, and the distillates caused 

 to crystallise at —7° C. In this way the methyl esters 

 of stearic, palmitic, and arachic acids were separated in 

 a pure state. — Parthenogenesis at Roscoff and at Berkeley : 

 Yves Delagre. A controversial paper in reply to Loeb. — '■ 

 The dispersion of light in interstellar space : Charles 

 Nordmann. .\ sketch of a new method for determining 

 if ravs of different wave-lengths all travel in interstellar 

 space with the same velocity, based on the monochromatic 

 photometry , of a variable star. The experimental results 

 will be given in a later paper. — Observations of the transit 

 of Mercurv of November 14, 1907, made at the Royal 

 Observatory of Belgium : M. Lecointe. Results are given 

 for the observations of the contacts, the form of the disc, 

 and observations of position and of physical appearance. — 

 Theorem on Taylor's series : Michel Petrovitch.-— The 

 approximate integration of differential equations : Emile 

 Cotton. — The diminution of the rolling of ships : Y. 

 Cremieu. — -A new series of ammoniacal ferric salts in 

 which the iron is masked : P. Pascal. K description of 

 some complex salts formed by the addition of ammonia to 

 solutions of sodium ferripyrophosphate. — The silicide of 

 magnesium : Paul Lebeau and Robert Bossuet. Alloys 

 of magnesium and silicon containing from 0-38 per cent, 

 up to more than 50 per cent, of silicon were examined 

 micrographically. From the results of this examination it 

 appeared that there exists only one magnesium silicide 

 containing less than 40 per cent, of silicon. Aqueous 

 solutions proved to be useless for the isolation of the 

 silicide from the ingot, and the excess of magnesium was 

 removed bv the action of ethyl iodide and ether. The 

 compound thus isolated was Si'Mg,, and gives hydrogen 

 free from hvdrogen silicide when acted upon by water. 

 Hvdrochloric' acid attacks it energetically, a mixture of 

 hvdrogen and spontaneously inflammable hydrogen silicides 

 being produced. The compound is completely dissociated 

 in a vacuum at iioo°-t2oo° C, the magnesium being 

 volatilised. — The colloidal properties of starch, and on the 

 existence of a perfect solution of this substance : E. 

 Fouard. The starch solution was filtered through a mem- 

 brane of collodion, and its properties were totally different 

 from ordinary starch solutions. The strength of the solu- 

 tion was 2-74 per cent, of starch ; it was clear and perfectly 

 transparent, and an intense light bundle after passing 

 through the solution showed no trace of polarisation. The 

 viscosity of a i per cent, solution was of the same order 

 of magnitude as water or i per cent, sugar solution, atid 

 onlv one-twelfth that of a i per cent, starch solution made 

 in the ordinarv way. — ^The state of the camphocarbonates of 

 thr' fattv and aromatic amines in solution, as shown by the 

 rotalorv power : J. Mirguin. — Rese.-nches on the physical 



