288 Electromagnetic and Electrostatic Unit of Electric Quantity. 



If now all the resistances be measured in ohms, the com- 

 plete expression for v becomes 



,,— a /A „ n + r a (s+g)U + sg M x 



VkfP n s (l + ±\).d 2 



In actual practice, of course, the mean of a large number of 

 discharges of the air-condenser was employed, and great care 

 had to be taken that the needle was absolutely at rest before 

 each discharge — since with such a large moment of inertia an 

 extremely small angular velocity meant a considerable angular 

 momentum, and consequently a considerable error if disre- 

 garded. Consequently, even when a number of weak auxiliary 

 checking currents were employed to stop the needle while 

 swinging after a discharge, considerable delay had always to 

 occur between two successive discharges, while waiting for the 

 needle to come to rest. 



June 18th. 



A = 1324*96 square centimetres, 

 t = 1*024 centimetre, 



P = 25-3 seconds, 

 r x = 3-0045 ohms, 



r t +r 2 = 8538 ohms, 

 B = 12000 „ 



8 1 



s+^-lOOO' 



d x = 297-34 scale-divisions, 



d 2 — 261*63 „ „ mean of 39 discharges. 



JX= 0-12095. 



"Weight of the magnet complete, with the forty magnets, the 

 wooden segmental pieces, and the mirror, 



2-15 grammes, 

 v = 297*4 million metres per second. 



June 23rd. 



A = 1323-14 square centimetres, 

 t = 0*7728 centimetre, 



P = 39*5 seconds, 

 r 1= = 3*0045 ohms, 



r x +r 2 = 10037*16 

 E= 12000 

 s = 19*955 „ 

 9 = 19733 



d 7 = 247*75 scale-divisions, 



d 2 = 221*93 ,, „ mean of 41 discharges, 

 J\= 0*07825. 



