OF WIRES FOR ELECTRICITY. 319 
Angles of deviation. 
Fa SSS SS 
1 2. 3. 4, |Average.|© 
Differences. 
any wire< the experiment...| 85°3| 89°7| 89°7 ook . : 
interposed | at its end *7| 89°3| 89°8| 88°53 88°31 | 88°52) +-0°21 
With interposed wire 7 feet long] 52°3) 52°4| 54°5| 53°4| 53°15 | 53°21|+-0:06 
— 14 38°2, 38:1] 39°6| 39°1} 38°75 | 38°51|—0-24 
21 29°7| 29°8| 31°5| 30°6| 30°40 | 30°25|—0°15 
— 28 24°3| 24°6| 248) 25-8] 24°87 | 24°93} +4 0:06 
35 20°9} 20°6| 22°0| 20°9) 21°10) 21°21/4+-0°11 
Without ' at the beginning of 
The calculation of the values of the 7th column was performed in the 
following manner. I took for the unit of the conducting resistance the 
length of 1 English foot of the wire, from which the five pieces had been 
cut, and represented the unknown strength of the current correspond- 
ing to this resistance by py: and I assumed z for the equally unknown 
conducting resistances of the wire of the multiplier and the electromotive 
spiral taken together. Assuming the hypothesis that the resistances 
of the wires are proportional to their lengths, and designating the devia- 
tions observed in the above table for the resistances 2, x + 7, + 14, 
&e. by oO, 4 p44 &c. we shall find, by means of the formule 
given in the former Memoir, the following equations : 
= p° sin (4) 
A — "Cy 1 
rary =p sin (37,47) 
A 
ein p-sin(g @ 454)" &e. 
Dividing the rest of the equations by the first, and designating the values 
sin (}a,,), sin (4 @,47) sin (La Cy 14)» &e. for brevity sake by a,a’, 
a", &e. we shall obtain 
ae 2; ; and therefore ax — y =0 
e+ 7= % —___— ax—y+7a'=0 (A) 
— a'x—yt+l4a"=0 
e+l4= 7 
a 
&e, 
