Chemistry and Physics. 337 



air had been removed by heating absorbed the emanation from 

 83 mg. of radium (about 0-05 cubic mm.) at —150° C. As the 

 temperature was slowly raised, less than one-tenth of the 

 absorbed emanation could be pumped out at — 50° C, as was 

 shown by measurement by the y-ray method. Above —40° C. 

 the emanation commenced to escape rapidly, and half had been 

 pumped off at 10° C. About 10 per cent remained at 100° C, but 

 practically all was released at the temperature of the softening 

 of glass. The results show that at 10° C. the charcoal absorbs 

 about 0*03 cubic mm. per gram, and at — 40° C about 0*06 cubic 

 mm per gram. — Chem. JVeios, xcix, 76. h. l. w. 



3. Method for Preparing Hydrogen Phosphide. — Matignon 

 and Teannoy have devised a simplified method for the prepara- 

 tion of the gas PH 3 . They mix powdered calcium phosphate 

 which has been previously calcined, in order to remove every 

 trace of moisture with powdered aluminium, in the proportions 

 required by the equation 



3Ca 3 (P0 4 ) 2 + 8Al 2 = 3Ca 3 P 2 + 8Al 2 3 



put the mixture in a crucible, heat it to dull redness, and ignite 

 it with an ignition mixture according to the Goldschmidt method. 

 The products of the reduction do not separate, but form a brownish 

 mixture, which after being broken up is suitable for the produc- 

 tion of hydrogen phosphide, by the action of water, followed by 

 hydrochloric acid towards the end of the operation. The result- 

 ing gas was found to contain 2 or 3 per cent, of hydrogen, but 

 otherwise it appeared to be perfectly pure.— Comptes Rendus y 

 cxlviii, 16V. h. l. w. 



4. The Theory of Valency, by J. Newton Friend. 12 mo, 

 pp. 180. London, 1909 (Longmans, Green and Co.). — This work 

 is one of a series of text-books of Physical Chemistry, edited 

 by Sir William Ramsay. Nine of these monographs have 

 already appeared, and five more are announced as in the course of 

 preparation. The book under consideration gives a concise 

 account of the more important theories of chemical combinations 

 w 7 hich have exercised the minds of scientific men down to the 

 present day. It appears that heretofore there has been no 

 treatise in the English language upon the important subject of 

 valency, while in German there is only one, a not very exhaustive 

 work which was published several years ago. The book will be 

 useful to students of chemical theory, since it covers the ground 

 very thoroughly and gives a very full list of references to the 

 literature. h. l. w. 



5. Recent Advances in Organic Chemistry, by A. W. 

 Stewart. 8vo, pp. xv, 296. London, 1908 (Longmans, Green 

 and Co.). — The author has endeavored to give an idea of some of 

 the most recent researches in organic chemistry which have been 

 carried out within the last ten years. The subject has been con- 

 sidered from a synthetic point of view and the work has some 

 commendable features, but is too condensed to be of much value 



Am. Jour. Sci.— Fourth Series, Vol. XXVII, No. 160.— April, 1909. 

 23 



