RESIDUAL WATER NUCLEI. 



much below. The successive values of b show an outspoken march into 

 larger values as the time / increases. 



If we combine the first observation with the fourth, etc., in series i, 

 x = o.2j, 6 = 0.0038, 0.0041, 0.0057, - I 34> or a mean value of b = 

 0.0045, if the last observation is ignored. But to ignore this value is 

 here quite inadmissible, as the data for series 2, where # = 0.25, viz, 

 6 = 0.021, 0.177, fully show. 



TABLE 51. Fog chamber standardized with radium (10 mg. io,oooX). Bar. 76.1 

 cm.; temp. 25. i C.; water nuclei precipitated. Exhaustions practically below the 

 fog limit of dust-free air. {>/p = o.268 to o. 272; distances 40 and 250 cm. 



74. Data for weak ionization. - -In the above work the initial 

 intensity of radiation was the same. It was suggested that the average 

 size of a nucleus might decrease in the lapse of time. Thus a variety 

 of further questions arise: (i) Whether weak radiation produces a 

 smaller average nucleus; (2) whether a stronger radiation does the 

 reverse; (3) whether the limit of b decreases as the exhaustion increases 

 and finally approaches b = o . ooi 4, etc. The experiments of the following 

 tables show that b varies with the number of nuclei present, no matter 

 whether a given nucleation is due to weak radiation or to decay from 

 a stronger radiation, or finally to low exhaustion; or that the nuclei 

 probably break to pieces as a whole. 



