34 KANSAS UNIVERSITY QUARTERLY. 
there is an indefinite number of pairs of valves of x, and x, that 
will balance the bridge, and if one inductance, say x,, is known, 
the other is readily found. 
To compare two self-inductances make x,—x,==0 in equations 
[6] and [7], giving j 
TyT [10] 
To —— ig iy [11] 
That is, the bridge is first balanced for continuous currents, then 
ed wt a 
—1 —_3 and the comparison is at once made. This is Maxwell’s 
oa 
method. 
To compare a self-inductance with an electrostatic capacity, ar- 
range the bridge as in Fig. 2. In this case the impedances of 
equation [3] are 
Z4=04—JX, Fis a 
Z3,—T3 
Zy—To 
eats 
1 lie wae . 
Xe—jX, 
Z, is obtained thus: 
I I £ I Xe—JI , 
Zy r, JXe Xe r, 
‘ I : : 
Where x, ar C being the capacity of the condenser connected 
W 
in parallel with branch (1). 
Substituting these values in [3] gives 
(t 4—)X4)Xe Tr, es 
Xe — Jt, aoe 
which gives the two equations 
Le Gr cr [12] 
k, kce bok, [13] 
I 
Peres, le pandas, —— 
Cw 
form given by Maxwell. 
and ‘[13] reduces to. L==Cryg ane 
bec 
A better practical arrangement of parts is shown in Fig. 3, where 
