54 NUCLEATION OF THE UNCONTAMINATED ATMOSPHERE. 



22, 26 30 34 38 42 46 80 2-1- 88 32, 36 40 



FIGS. 52-55. Illustrating tables 30, 31. 



Tab. 3, in the above chart, is replaced by the present table 30 in the text ; Tab. 4, by the present 



table 31. 



GENERATION AND DECAY OF NUCLEI. 



47. Fleeting nuclei. This brings the work to the main purposes of 

 the present paper, viz, to compare the generation and decay of the 

 nuclei produced by the X-rays when the density of ionizatiou or of 

 electrification has different values. It was shown conclusively above 

 that with strong radiation the nuclei persist for hours, and it follows 

 from the foregoing paragraphs that for weak ionization they are fleet- 

 ing. Hence there must be transitional conditions, and these are to be 

 investigated, both for the production and for the decay of nuclei. 



With such an end in view a strong X-ray tube may be placed at 

 different distances from the end of the fog chamber and the results 

 referred to the nucleation within, or the same bulb in the efficient and the 

 partially fatigued condition may be placed at a fixed distance near the 

 apparatus. The second method is usually inseparable from the first. 



44- 



