183 
the Magnetic Permeability of Nickel and Iron 
Jo 
Fig. 
SoLeNnoiID 
<~- EAST Wrest —> 
C, Maenetometer-coil. R. Copper field-ring. M. Magnetometer, ©, Compensating-coil for heating circuit. 
C,. Compensating-coil for aplenoi. 
enamemreneenrormr] VLEET 
EER SOME SAMS ONES PEGE ES aa, Pas 
gytechewmnan aa _ - 
ie 2 
Heating Apparatus. 
