CONTEMPORARY ADVANCES IN PHYSICS 217 



160, 304 (1937) ; Blackett, ibid. 165, 1 1 (1938) ; Wilson, iUd. 166. 482 (1938) ; Leprlnce- 

 Rine;uet and Crussard, Comptes Rendus 204, 112, 240 (1937); Ehrenfest, Comptes 

 Rendns 207, 573 (1938). 



Penetrating particles detected with counters, with or without cloud- 

 chambers: Street, Woodward and Stevenson, Phys. Rev. 47, 891 (1935); Street and 

 Stevenson, Phys. Rev. 51, 1005 (1937); Auger and Ehrenfest, Comptes Rendus 199, 

 1609 (1934). 



Tracks of particles with characteristic ionization densities: Electrons: 

 Corson and Erode, Phys. Rev. 53, 773 (1938). Mesotrons: Street and Stevenson, 

 Phvs. Rev. 52, 1003 (1937); Ehrenfest, Comptes Rendus, 206, 428 (1938); (E. J.) 

 Williams and Pickup, Nature 141, 684 (1938); Maier-Leibnitz, Naturwiss. 26, 677 

 (1938); Neddermeyer and Anderson, Phys. Rev. 54, 88 (1938), and literature there 

 cited. 



Theory of showers: Oppenheimer, Phvs. Rev. 50, 389 (1936); Carlson and 

 Oppenheimer, ibid. 51, 220 (1937); Bhabha'and Heitler, Nature 138, 401 (1936), 

 Proc. Roy. Soc. 159, 432 (1937) ; Bhabha, Proc. Roy. Soc. 164, 257 (1938) ; Montgomery 

 and Montgomery, Phys. Rev. 53, 955 (1938). 



Deflections of particles: Blackett and Wilson, Proc. Roy. Soc. 165, 209 (1938). 



Electron's recoiling from imp.\cts of mesotrons: Wilson, Nature 142, 73 

 (1938). 



Instability of mesotron: Blackett, Nature 142, 992 (1938); Rossi, ibid. 993; 

 (T. H.) Johnson and Pomerantz, Phys. Rev. 55, 104 (1939). 



General reviews: Euler and Heisenberg, Ergebnisse d. exakten Naturwiss. 17, 1 

 (1938); Froman and Stearns, Rev. Mod. Phys. 10, 133 (1938). 



