Chemistry and Physies. 431 
11. On the electric discharge in Rarefied gases—Dr. EvcEn 
GopstEIN, in a preliminary paper on a new differentiation of 
rarefied gas, takes place only when the ray strikes upon a solid 
obstacle. (2.) It is not the whole length of the ray which pro- 
duces the ngnt, but only the end of it furthest from the negative 
pole. (3.) The cause of the production of the light is to be 
sought in an optical action. (4.) The Breuer of the bat of 
the ray is produced, not only when the mpinge a 
pea wall, but also whenever it falls on ay solid substance 
(5.) T differentiation | 1n sar is not associated with a par- 
teaaes prone (6.) The phenomenon is not associated with 
any pa baa inteblilg of discharge. (7.) The same differentia- 
tion occurs with the “ secondary negative light,” a name given to 
the light produced at any point of the discharge at which a 
Contraction of the tube is introduced. (8. e excitation of 
light by the ends of the negative rays is not of the same kind as 
the illumination called forth in the surrounding walls of the tubes 
by the stratification of the positive nen when the veritatis is 
small.— Phil. Mag., September, 1880, p. 173 
Dr. Goldstein’s paper is to be ricoh se and will prove of aces 
interest in connection with Crookes’ experiments in ane 
direction os 
12. Heat theory of the development of Electrici se aie L. 
Hoorwee maintains the theory that the development of electricity 
is due to a redistribution of kinetic energy in the form of heat. 
Electricity results from thermo-dynamic relations ni seven the 
points of contact of heterogeneous substances. Peltier’s phe- 
nomena—the development of electricity from ev ph news from 
iffusion, from osmone, from psa re, in turn, discussec med 
, 1880, 
ndemce to he wads of Chemical Reactions ; Pat 
Part, Epmunp Drecuset. ‘Translated by N. Fred. Merril, Ph. D. 
New York: pare Wiley & Sons. 138 pp. 12mo,—This volume 
is occupied with the application of the most recent and advanced 
rarest er i to the elucidation of the chemical changes 
that a ved in elementary qualitative analysis. The wo ~ 
of both authér and translator is excellently done. The term 
Molecules, Atoms and Reactions are first defined; Valence a 
its laws ; Oxidation and Reduction; Solution of Metals and 
Metallic Oxides; Manner in which Reagents work; Characteristic 
and Special Reactions of Bases and Acids, are the titles of the 
pre ses, he chapters. The book must be very serviceable to 
students of analytical chemistry in acquiring pegaiariial see se 
theory of their 
14. Water "analysis = Sanitary purposes, with hints foe the 
interpretation of results; by E. Franxianp. 149 pp. 8vo. 
Philadelphia, 1880 (Presley Blakiston).—This little volume gives 
