﻿320 Dr. P. E. Shaw on the Disruptive Voltage of J hin 



Then the spindle B is moved slightly away, the liquid being 

 thus drawn out into a thread connecting the surfaces, and 

 there is a guarantee that liquid without air-bubble connects 

 the surfaces. The switches K 2 and K 3 are put to the left,. 



Fkr. 2. 



US.T 



and K 5 and K 6 put over to the right. If nowjo is advanced 

 and touches q, the telephone T sounds ; the reading of the 

 divided head of the right micrometer-wheel is taken. This 

 is the first reading. The surface q is drawn away from p 

 about twice as far as the spark-length about to occur. 

 Switches K 2 and K 3 are put to the right, and K 5 and K 6 put 

 to the left. The position of Z 2 is arranged so that the volt- 

 meter shows the desired P.D. Now K 5 and K 6 are put over 

 to the right, and g is mnde very slowly to approach p, the 

 micrometer-scale being watched so that at the moment when 

 discharge occurs and is indicated by the sounding of telephone 

 L.S.T., the scale is read a second time. The discharge-distance 

 is the difference between the first and second readings. 



