Mathema Tics: C. M. Cleveland

cordance with the mechanism proposed by Jahn, the temperature coefficient leads to a value for the heat of dissociation of ozone into molecular okygen and atomic oxygen. Calculating by thermodynamic methods the concentration of monatomic oxygen at 1000 and 1 atmosphere pressure in 5% ozone, and by kinetic theory methods the number of collisions between molecular ozone and atomic oxygen, it has been shown that these collisions are many times too small in number to account for the observed rate and hence that the Jahn mechanism cannot be regarded as tenable, at least in its original simple form. * NATIONAL RESEARCH FELLOW IN CHEMISTRY. 1 Warburg, Ann. Physik, 9, 1286 (1902). 2 Clarke and Chapman, J. Chem. Soc., 93, 1638 (1908). 3 Perman and Greaves, Proc. Roy. Soc., A80, 353 (1908). 4 Griffith and McKeown, J. Chem. Soc., 127, 2086 (1925). 6 Jahn, Zeit. anorg. Chemie, 48, 260 (1905). 6 Chapman and Jones, J. Chem. Soc., 97, 2463 (1910). 7 Earlier observations of the influence of temperature on the specific rate had been made by Warburg (loc. cit.); Clement, Ann. Physik, 14, 341 (1904); and Perman and Greaves (loc. cit.); and recently by Belton, Griffith and McKeown, J. Chem. Soc., 129, 3153 (1926).