58 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



five independent series of measurements of the fall of the potential of 

 the core per second. The following is the summary, referring to the 

 negative current, where C is 136 cm., 7=1.87 cm. /sec., P=i8.8 cm., 

 = 2.i cm., 2^2 = 0.62 cm. 



When the condenser was disconnected there was no leakage, showing 

 the piping to be nearly free from such currents as might result from 

 irregular penetration of the gamma rays. The approach of the final 

 values of e to those currently in use is no closer than before. It has again 

 been assumed that negative ions only have been caught in the fog cham- 

 ber, and that a negative current alone is in question when the core (con- 

 nected with the electrometer) is charged positively and the shell of the 

 condenser is put to earth. 



47. Conclusion. The values of e obtained under widely varied con- 

 ditions in the present rough experiments, are of the same order and to 

 this extent show that the present method is not unworthy of develop- 

 ment, with a view to the further measurements of this important con- 

 stant. For this purpose I have been at work on a redetermination of the 

 nucleation values of the coronas (see Chapter II), using as a source of 

 light the virtually monochromatic mercury lamp. This is sufficiently 

 intense and the coronas admit of a more definite optical interpretation. 



All of the e values are too high, however, when it is assumed that a 

 negative current only is in question and that negative ions only are 

 caught. The reason for this high value of e is probably referable to the 

 aluminum-brass condenser, which contains an electromotive force not 

 allowed for nor eliminated by commutation. Such a case would modify 

 the ratio V/V in the above results by changing the zero-point of the 

 electrometer. The experiments were abandoned at this point owing to 

 the dampness of the summer season. They will be resumed in Chapter V. 



