66 
Prof. D. N. Mallik : Experimental Determination 
approximately spheroidal in form of very mild Bessemer steel 
well annealed, and the coil DC was wound round a thin wooden 
cap which just fitted it to half its length. 
A current, the constancy of which was indicated by an 
ammeter, being passed through the coil, the soft steel rod was 
magnetized, and the object of the experiments was to explore 
the magnetic induction over the projecting portion of the rod. 
3. In order to do this, a thin coil \ inch in thickness 
having 36 turns (six turns, six deep), in series with a ballistic 
galvanometer, was slipped over the rod and placed at different 
positions beginning with middle of rod (the zero position), 
and corresponding throws on the reversal of current were 
noted. In the preliminary experiments (I. and II.) the thin 
coil was placed at random at different positions which were read 
Fig. 2. 
IV 
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Axial Distances from Zero or Central Position of Thin Coil (in cms.). 
off by means of a telescope. The results are represented by 
Curve I., fig. 2, in which abscissas represent distances from 
