874 
New method for making oscillographic records of the number 
of lines of force. 
If we desire to make an oscillographic record of the number of 
lines of force in an iron path or an airgap, a few insulated copper- 
windings are laid round the iron or a small coil is placed in the 
air gap. When the number of the lines of forces 6 varies, an 
com wie doe ; : , 
electromotive force V = k- 7 generated. The terminals of the coil 
( 
are connected with a condenser of a capacity C. This takes up a 
charge g = VC and tbrough the coil and the connecting wires with 
a total resistance r we have a current t. 
Now we can state: 
dq db 
ba ka and kandi ren en rie. Die RE 
After substitution we get: 
k oe =n, ay 4+ V 
dt dt 
and putting m= Ae 
ey o 
dt Cine: 
which gives after integration: 
Aly. ifs 
B=AV+ =), Vidi ees Kanst.ait) srt. ceil sete Ss Bian 
rc 
