124 



VAPOR NUCLEI AND IONS. 



Fig. 57a. Disposition of coronal apparatus for measuring atmospheric nucleation 

 ("dust"). V, vacuum chamber; F, fog chamber; G, goniometer; g, gage; e, exhaus- 

 tion pipe; t, support for trunnions. Influx pipe at left end of fog chamber. 



Fig. 576. Disposition of apparatus for measuring atmospheric ionization. E, Ebert's 

 apparatus; B, swiveled brackets sustaining the same; T, thermometers. 



ling's paper contains. Reference should also be made to P. Langevin's* 

 important discovery of slow-moving ions in the atmosphere and to the 

 work of M. Bloch.fbut comparisons of this nature are quite beyond the 

 scope of the present straightforward experimental research. 



86. Measurements of nucleation. Number of nuclei in the atmosphere 

 were measured by aid of the corona of cloudy condensation, in the way 



* P. I y angevin: Bull. Soc. Fran^. de Phys., p. 79, 1905. 



fBloch: "Recherches sur la conductibilite' dlectrique, etc.," Paris, 1904. See C. T. R 

 Wilson, Trans. Intern. Congress, St. Louis, vol. 1, p. 365. 



