Chemistry and Physics. 317 



According to the second method hydrazine hydrate is heated 

 with barium oxide at 100° and the product is distilled under 

 diminished pressure. Free hydrazine is a liquid which boils at 

 113-5° (at V61 mm ). By cooling below 0° it solidifies, and it melts 

 at 4-1*4°. Its specific gravity is about the same as that of the 

 hydrate, 1*003 (23°). It is a very stable body and can be heated 

 above 300° without decomposition. The halogens act upon it 

 with great violence, and it acts upon solid sulphur at ordinary 

 temperature with the formation ol hydrogen sulphide. Oxygen 

 attacks the base, with the liberation of nitrogen, when it is 

 exposed to the air. The author has also made the useful obser- 

 vation that hydrazine hydrate can be distilled under diminished 

 pressure from glass vessels, since under 50° it does not attack 

 glass. Curtius, operating under atmospheric pressure, was 

 obliged to use a special apparatus of silver for the distillation. — 

 Merichte, xxviii, 3085. h. l. w. 



6. Practical Inorganic Chemistry, by G. S. Turpin, 12mo, 

 pp. 158, London and New York, 1895. (Macmillan & Co. Price 

 60 cents.) — This is a course of laboratory work for beginners in 

 chemistry. The experiments are very simple in character, and 

 are such as can be carried out by very youthful pupils with lim- 

 ited facilities. Many of the operations are of a rough quantita- 

 tive nature, designed as illustrations of chemical and physical 

 laws. While the processes are clearly described, the results, in 

 most cases, are not mentioned, so that the student is obliged to 

 observe them for himself. A chapter is devoted to a very simple 

 course in qualitative analysis, covering a range of seven metals 

 and four acids. h. l. w. 



7. Chemical Experiments, General and Analytical ; by R. P. 

 Williams, 12mo, pp. 110, Boston, 1895 (Ginn & Company). — This 

 book is intended for a somewhat comprehensive course of labora- 

 tory work in high schools, academies and colleges. The subject 

 matter is condensed, abbreviated and tabulated to a large degree. 

 It seems that more help should have been given to the student in 

 the way of explanations. Upon the mere mention of such words 

 molecule, affinity, stochiometry, definite proportion and the like, 

 the pupil is expected to study these subjects " outside the labora- 

 tory," and he is expected to write chemical equations, although 

 none are given in the book, even in some instances where the 

 products of the reactions are not mentioned. Unfortunately the 

 book contains a number of astonishing inaccuracies. h. l. w. 



8. A Text Book of Gas Manufacture for Students ; by John 

 Hornby. 12 mo., pp. 261, London, 1896 (George Bell and Sons). 

 — This little book gives an excellent account of the subject in 

 view. The chemical and mechanical features of the processes are 

 clearly described and the illustrations are numerous and well- 

 chosen, h. l. w. 



9. Methods of determination of Dielectric Constants. — W. 

 Nernst refers to his method of measuring the dielectric constant 

 of insulators and bad conductors (Zeitschr. f. Phys. Chem. xiv, 



