H. A. Rowland—Absolute Unit of Electrical Resistance. 289 
be noted that this earth-inductor is the same as that used by 
Weber in his experiment of 1862; and which also gave a larger 
value to the Ohm than those of the British Association Com- 
mittee. Indeed, the results with this inductor and by this method 
form the only cases where the absolute resistance of the Ohm has 
Association Committ 
There seems to be a small one-sided error in A and B which 
Kohlrausch does not mention, but which Weber, in his old 
experiments of 1851, considered worthy of a 6 per cent cor- 
been found greater than that from the experiments of the British 
tee. 
Needle by the earth-inductor, and y is the velocity as deduced 
from the ordinary equation for the method of recoil, I find 
pon) CA et 
more exact to substitute 
4 (fy f"s sin t di==4 (=) 
a/J a 
in the place of 72. The formula then becomes 
2 \2\ 1-44 
emis (6) (at) pt 
re exact when A is small than when it 
is large, but it is sufficiently exact in all a to give — 
: how long it took him to 
Source. Kohlrausch does not state g halk about 
