of the above 



salts, preferably the sul- 



15 per cent 



of concentrated sulphuric 



lor changes to 



a dark red, and, afterward 



58 Scientific 



aqueous solution of 

 phate, eo 



acid, be boiled till il 



be extracted with ether, the ether leaves on evaporation crystal- 

 line masses which on sublimation give colorless needles, which 

 dissolved with water and treated with ferric chloride, yielded 

 magnificent green needles having a metallic luster. This sub- 

 stance is hydroquinone and the yield is 46-2 per cent, the theo- 

 retical being 50.— Ber. Berl. Chetn. Ges., ix, 1159, Sept., 1876. 



6. On G'i ns. — Sonnkhschkin has examined 

 the root of the wild jasmine and has isolated its alkaloid, gelse- 

 mine, to which he gives the formula C , , H t 9 N0 2 . The substance 

 called by Wormlev gelseminic acid, he finds to be esculin. — Ber. 

 Berl. Chem. Ges.,\x, 1182, Sept, 1876. a. f. b. 



7. Kurae ',ung zu den aromatischen Nitro-ver- 

 !,;,,.h, ,,,,,>,, von I'ku.u TowNSK.vn Austen. Pamphlet, 43 pages. 

 Leipzig: Winter, 1876.— This little work possesses a peculiar 

 interim!, as ir i- the attempt of an American to produce a compre- 

 hensive treatise in a foreign language and country. The manner 

 in which Dr. Austen has treated this class of organic compounds 

 differs greatly from the general style of monographs, and is cer- 

 tainly practical and original. The work is intended to afford all 



96 working on researches involving the nitre- 

 is such that the facts sought for 

 can readily be found. The style of the book is clear and remark- 

 There is no doubt but that similar treatises on various other 

 groups of organic compounds, such as the hydroxyl, amids, and 

 many others, would enormously facilitate the labors of chemists 

 engaged on original research. 



The book is dedicated to Prof. A. W. Hofmann, of Berlin. 



8. Mariotte's Zaw.—Proi. Mexdeleeff, at the Warsaw meet- 

 ing of Russian naturalists, described the results of researches he 

 has pursued during 1 875 and 1876, for the verification of Mariotte's 

 law. His former researches had proved that the decrease of vol- 

 ume of the permanent gases proceeds at a slower rate than the 

 increase of pressure exerted on them, if the pressure is less or 

 much greater than the mean pressure of the atmosphere. The 

 experiments of Regnault, made with air, nitrogen, etc., at pres- 

 sures higher than that of the atmosphere proved, however, di- 

 rectly the contrary, and a series of measurements undertaken some 

 years ago by I'iof. Mend. 'lea-it* to verify those of Regnault, gave 

 the same results. Suspectiiii: that there might be some cause of 

 error affecting in the same way both series of experiments, Prof. 

 Mendi paratua elim- 

 inating all possible causes of errors and allowing the most perfect 

 accuracy of measurements. With these they made a new series 

 of r - -arches, at pressures varying from 700 to 2,200 millimeters. 

 These researches confirmed again the conclusions of Regnault, 





