ELECTROMAGNETIC UNIT OF ELECTRICITY TO THE ELECTROSTATIC UNIT. 619 
Column 18 contains the values of y which result when all these corrections ar<i 
made. 
Column 19 contains the values of the electromagnetic measure of the capacity 
calculated from the formula 
C = • 
n^b 
Since the auxiliary fork makes 21 heats per minute with the standard fork, which 
makes 128’1045 vibrations per second, and since the observing fork makes half the 
number of vibrations of the auxiliary fork 
n = 63-8773. 
Assuming that the B.A. unit = '9867 X 10^ in absolute measure which corresponds 
to the legal ohm being '9978 X 10’’, we have 
(j _ 7 X 
b/3 X Go'S77o X ’9977 
We have supposed that the resistance to the variable current which passes through 
the resistance coils during the charging of the condenser, is the same as the resistance 
to a steady current. This is justified by the following investigation. Though in our 
experiments the resistances were so large that the charging was not oscillatory, let 
us suppose that it is oscillatoiy and has the maximum frequency 1 / x/LC. Then if r' is 
the resistance to this oscillatory current, r the resistance to a steady current 
•r = y I 1 kit '[, 
Avhei e I' is a small munei ical coefficient and 
TT (O 
'' v/fiC ^ ’ 
where a is the radius of the cross section of the wire, and a its specific resistance. The 
coefficient of self induction of a galvanometer similar to the one we used -was found 
some time ago to be 5 X 10®, cr = 2 X 10*^ and a = ‘023 for 32 B.W.G. ; substituting 
these numbers we find n = 10“® about, and 
n" = 10 “b 
so that the correction will only amount to one part in a million, and may be 
neglected. 
The mean of the first set of observations = 443-471 X 10“'h 
,, second ,, = 443-417 X 10~^b 
,, third ,. = 443-569 X 10~'h 
The mean of all the observations . . = 443-486 X 10 “'h 
4 K 2 
