PEIRCE. — ESTABLISHMENT OF CURRENT IN COIL. 



153 



TABLE I. 



Figure 2 represents Table I graphically in the full curve, B A,' 

 one vertical unit corresponding to a hundred thousand maxwells, 

 and one horizontal unit to a hundred ampere-turns. There is evi- 

 dence of slight eddy-currents at the outset, but the effect quickly 

 disappears and the magnetization curve follows closely the march of 

 the current. The slopes of the curve B A, were found in the follow- 

 ing way : After the curve had been drawn on a large scale to represent 

 the numbers of Table I, a zinc templet was made from it, as accurately 

 as possible; this was fastened down on a drawing-board over a large 

 sheet of coordinate paper and the value of the slope ^ ( T) was deter- 

 mined by measuring on the paper the position of a straight-edge which 

 was held tangent to the templet at any desired point. These slopes 



