UNITS IN THE ELECTROMAGNETIC UNIT OF ELECTRICITY - . 
721 
Resistances in the various arms of the Wheatstone’s bridge, when there was 
no deflection of the galvanometer. 
Resistance in 
the arm A D. 
Resistance 
in B C. 
Resistance 
in A C. 
1 . 
899,666 
99,920 
1294 
2. 
899,666 
99,920 
1285 
3. 
899,930 
99,950 
1297 
4. 
899,700 
99,925 
1287 
5. 
S99,700 
99,925 
1297 
The mean of these 
correct to 1/10 per cent, is 
899,700 
99,925 
1292 
According to Lord Rayleigh’s determination of the ohm the B.A. unit 
= ’987 X 10 9 
so that from the formula viC=ct/cd we find that the electromagnetic measure of the 
capacity of the condenser =’4517 X 10 -19 . 
The electrostatic measure of the capacity of the same condenser is 396’8. 
So if v be the ratio of the electrostatic unity of electricity to the electromagnetic 
q 396-8 xlO 19 
V '~ ~ -4517 
v=2’963 X 10 10 in C.G.S. units. 
Some experiments were made with a tuning-fork vibrating 44 times a second; the 
results of those were found to agree very closely with those obtained when the 
tuning-fork vibrated 32 T8 per second. The above experiments were made in the 
Cavendish Laboratory, Cambridge, and I have much pleasure in than king Lord 
Rayleigh for the very valuable advice which he gave to me throughout the 
investigation, as well as for his kindness in designing several of the more important 
pieces of apparatus. 
