ASSOCIATION UNIT OF RESISTANCE IN ABSOLUTE MEASURE. 
685 
Correction for torsion. 
To determine r, about five complete turns in either direction were given to the 
upper end of the fibre. The difference of reading for one turn was found to be in 
June 2*58, and in August 2 - 45. If we take as the mean 2’51, we get 
T = 
2-51 
47r x 2670 
= ‘000075 
Value of GK corrected for level and torsion. 
Calling the corrected value we have 
so that 
GrK(l + tan 1/3) 1-00019 ^ 
1 + T — 1-000075 G 
log <2*E=8-17686 
The corrections are in fact almost insensible. 
Calculation of U, 
In this we take for the value just found. For L we take the mean of the 
values found by a priori calculation and by direct experiment, i.c., 
Thus 
L=2'4026 X 10 s . 
log (li = ' 50485. 
2L 
= 3*1978 
For the values of tan <j> and tan </> 0 we must anticipate a little. The ratio is itself 
in some degree a function of the speed, but it will suffice to take the values 
applicable to the highest speed, for which tan </> 0 : tan </> = 7‘81 : 439'41. 
Thus 
and 
tan cf) 
tan (f> — tan <p 0 
= 1-0181 
log U=*84325 
