Chemistry and Physics. Ill 



this source. From about 2 kg. of the metal they obtained nearly 

 4 decigrams of gallium, or a yield of nearly '02 per cent. Unfor- 

 tunately the authors describe their method of extraction only very 

 vaguely. They say that the aluminium was treated with hydro- 

 chloric acid, that the impurities were separated by means of 

 hydrogen sulphide, either in hydrochloric or acetic acid solution, 

 and that the separation was repeated several times. Probably 

 the gallium was precipitated with the sulphides obtained in acetic 

 acid solution, and thus separated from aluminium, but this point 

 is not made clear. — Comptes JRendus, clvii, 718. h. l. w. 



3. Ammonium Peroxides. — A number of years ago the com- 

 pound NH 4 2 H (or NH 3 .H a 2 ), ammonium hydro -peroxide, 

 was prepared by Melikoff and Pissarjewski. Recently D 'Ans 

 and Wedig, by passing dry ammonia into a solution of 98 per 

 cent hydrogen peroxide in absolute ether, at a temperature of 

 about —10° C.j have obtained at first beautiful transparent crys- 

 tals of the compound mentioned above. When more ammonia 

 was passed in, the crystals melted and a heavy oily layer settled 

 out of the solution. The ether then contained much ammonium, 

 but only traces of hydrogen peroxide. The oily layer solidified 

 with difficulty at —40° C, and the crystals thus formed were found 

 to be in the new compound (NH 4 ) 5 O s , or ammonium peroxide. 

 This compound readily loses ammonia with the formation of the 

 other peroxide. — Berichte, xlvi, 3075. h. l. w. 



4. The Poison of Toads. — Wieland and Weil have succeeded 

 in obtaining in a pure condition the poisonous principle excreted 

 from the glands in the skin of toads. They employed the skins 

 of 2000 toads and extracted the crude substance by a long series 

 of operations, obtaining about 20 g. of it. This amorphous prod- 

 uct had been obtained previously and named bufotalin. It was 

 known to be free from nitrogen, like the snake poisons. The 

 present investigators wei*e able to purify the product and obtained 

 it in the form of beautiful, transparent, colorless crystals. It 

 was found to have the composition C 16 H 24 4 , to be optically active 

 and neutral in its reaction. By a study of its chemical behavior, 

 a considerable, but not complete, knowledge of its structure was 

 obtained. — Berichte, xlvi, 3315. h. l. w. 



5. Quantitative Analysis in Practice; by John Waddkll. 

 8vo, pp. 162. Philadelphia, 1913 (P. Blakiston's Son & Co. Price 

 $1.25 net). — This book presents an introductory course of anal- 

 ysis designed for colleges and universities. Very full and excel- 

 lent directions are given for the exercises for practice, which, 

 after the complete analysis of barium chloride, magnesium sulphate, 

 and calcium carbonate, consist chiefly of technical analyses of 

 ores and a few other commercial products. Much good advice is 

 given in connection with the operations. There is a section de- 

 voted to the inculcation of honesty, which might well be made even 

 more emphatic ; accuracy and speed are also discussed, and a very 

 good feature of the book is the statement of the time that should 

 be required for each analysis. It is inevitable that there should 



