OP ARTS AND SCIENCES. 115 



Average distance apart, .5 era. 



Capacity (geometric) 5317.9 absolute units, — corrected for the 



capacity of ends. 

 Capacity of wire, 200. 

 Self-induction, in three sections, radius, .0501. 



1. Length, 1197. 



Distance apart of parallel wires, 31.55. 



2. Length, 281. 

 Distance apart, 16.10. 



3. Length, 103. 

 Distance apart, 11.3. 



For alternations of slow period. 



Ohmic resistance, .742. 



Self-induction, 41090. 



Theoretical time with these values, .00000310 sec. 

 For alterations of period, .00000310 sec. 



Ohmic resistance, 1.54. 



Self-induction, 39700. 



Theoretical time, 00000304. 

 Distance from spark to concave mirror, 230 cm. 

 Distance from rotating mirror to negative, 259.7 cm. 

 Sparking distance, .23 cm. 



The following is a sample record (see Figures 5 and 6). Each 

 negative was measured three or more times, and the mean taken. 

 The lengths are given in centimeters. The last line is the time in 

 millionths of a second. 



2.62 3.45 3.25 3.01 2.85 3.22 3.12 



Number of revolutions per second, 54. 06. 

 Length of spark, .23 cm. 



