Electroscopie Measurements and their P 



revention. 



281 



The values H 2 and H 3 obtained are both equal to Hj and A. 

 The leak obtained thus is referred to as the normal leak. 

 Leaks such as B, D, or F obtained after repeated charging 

 of the leaf to the same potential of one sign are denoted as 

 maximum leaks. Leaks C, E, and G obtained by altering 

 the sign of the potential at the maximum points are denoted 

 as minimum. The maximum leaks, whether obtained by 

 positive charging or negative are all equal and so are the 

 minimum leaks. 



The effect of altering the sign of the charge at any point 

 was next tried. At a point such as J 1? which is between the 

 normal and the maximum leak, if the sign of the potential 

 be reversed, the leak falls to K 1? which, however,, is greater 

 than the minimum leak. It was found that the nearer the 

 point J is to the maximum the nearer will K be to the 

 minimum and rice versa. The same holds also for a point 

 between the normal and the minimum leaks. 



The curve J l5 Kj, J 2 , K 2 , J 3 , K c , J 4 shows this. The graph 

 of a succession of readings taken by charging alternately 

 positively and negatively therefore would be an oscillatory 

 curve in which the oscillations get smaller and smaller until 

 they cease altogether. This would hold true if the charging 

 up each time were done perfectly, but slight variations in 



Kg. 2. 



t D 90 



TiME /A/ M/A'UTlS- 



this, which will be discussed later, cause variations which 

 prevent the oscillatory curve from developing into a straight 

 line. Some results illustrative of this are plotted 

 where the initial and final leaks are normal leaks. 

 Ionization bv an external source preceding 



in 



fig- 2, 



char firing, 



provided it is intense enough, always gives the normal leak. 



