Barus — Ionization of Water and Phosphorus Nuclei. 223 



denser length is I = 50 cm , the combined velocity of the charge 

 in the unit field is U = *015 cm./sec. 



From considerations relating to the viscosity of the medium 

 it was found that i?Z7= # 125xlO~ 6 and if Z7is taken equal to 

 *015 cm./sec, as just stated, i?= 8X10" 6 follows for the radius 

 of the water nucleus. A superior limit H= io~ 5cm would fol- 

 low from subsidence considerations. 



From direct experiments on the diffusion of nuclei (this 

 Journal, xiv, 225) for solutions of initial concentrations of *01 

 per cent and -0001 per cent, k — '0013 and *03 cm./sec, respec- 

 tively. These values of Jc are necessarily much smaller than 

 UJ?/{?\ — ?\), and the data are confirmatory. 



From measurements of the apertures of coronas, n = 10 3 to 

 10 4 nuclei per cubic centimeter. 



In case of phosphorus nuclei, Jc= '3 cm./sec for the velocity 

 of the nucleus in a given direction, and in the absence of the 

 electric field was found directly from experiments with the 

 steam jet and absorption tube. 



In the electrometer work with this emanation, U= '07 cm./sec 

 and i?=l-9XlO~ 6cm follow from a final comparison of the 

 nucleation data n ' for plate or spherical condensers (full satu- 

 ration) with the nucleation of tube condensers, n Q (deficient 

 saturation), since here U=hnJ?i '. Thus £7 increases with n 

 and if ?? , by specially devised methods, is increased to 2?i 

 (which has been possible), £7=*11 cm./sec. and i? = 10 

 follow. 



Finally the nucleation for complete saturation wasw =5Xl0 6 

 nuclei per cubic centimeter; but if U can be raised to '14 

 cm./sec. as just stated, ?? =2Xl0 6 . The nucleation of the satu- 

 rated phosphorus emanation thus exceeds a million per cub. cm. 

 at the surface of>the phosphorus. It is, therefore, larger than I 

 at first made out, and in a subsequent paper I shall show that 

 the same order of values follows from the purely optical experi- 

 ments made with coronas. 



It is because of this general consistency in the results of 

 experiments so widely different in character, that I venture to 

 adhere to the essentials of my old hypothesis. 



Brown University, Providence. 



j 

 6 cm 



