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S E T BOOKS
that one does not think of it as n i,efcrencc 7vo1.k hut i n c'iitc.i,t,:iining story of t i i t ' progress of thc pliysii~alscicnc The. pi,inting, pal)rr, :ind tiinding l l r r very gor>tl. , T o m I!.' GRCNER.
Cheritical Kineiics m t l Chain 12eacliuns. By N. SEMESOE'F. 480 pp. Oxfoi,tl: C'larendon Press, 1935. Price: $10.50. One of the most important developments of chemiral kinetics since the discovery of chain mechanism by Rodenstein in 1912 has been the introduction by Semenoff of the theory of chain branching and chain breaking. He has shonn how the combinntion of these two competing processes, the one increasing, the other diminishing the number of reaction chains, completely controls the kinetics of many types of reaction, especially those of ignition, flame propagation, and explosion. The author has expressed the viea- that chemical kinetics requires complete rercinstruction from the standpoint,of chain mechanism. The results of this undertaking he presents in a inasterlyway in the present work. After developing the general theory and equations he treats the experinirntiil material in three parts of several chapters each, one on reactions involving the halogrns, one on oxidation, and one on decomposition and polymerization. Tht. upper and Ion-er limits of pressure in gaseous explosions are discussed in about ii dozen systems each, the induction period and time lag, the effect of wall, of the addition of nitrogen peroxide, of water vapor, and of inhibitors and inducers are thoroughly discussed. The ivork is thoroughly modern and represents t,remendous progress in the very difficult and complicated field of chemical kinetics. 8.
