104 Bakret'I', Bkown & IIadfield — On the Electrical Conductivity and 



The following Is an example, taken at random, of the readings obtained in 

 going through a complete cycle for one of the specimens ; from these readings 

 the data necessary for plotting one of tlie curves given in Plates III.-IX. are 

 obtained. 



Table I. — (Mauk 1179 B, Plate VIII.) Ckyominm-Alnminium Steel. 



Column 1 gives the number of the steps, first up and then down, as already 

 explained, p. 102. Column 2 gives the magnetising current round the coil in 

 amperes ; these numbers multiplied by 30-2 — the magnetic force of the coil per 

 ampere — give the magnetic force H, acting on the rod in C.G.S. units. Columns 



3, 4, and 5 give the magnetometer readings corresponding to the currents named 

 in column 2 ; the sign + means a reading to the right of zero, and the sign — a 

 reading to the left of zero. Tn columns 3 and 5 the current through the magnetising 

 coil is in one direction ; in column 4 it is reversed. Referring to fig. 8, the initial 

 uprising curve 1 is obtained from the magnetometer readings enclosed within the 

 first bracket in column 3 ; the position of the curve 2 in fig. 8 is obtained from 

 the readings in the second bracket in column 3 ; the current is now reversed, and 

 the portion of the curve 3 in fig. 8 is obtained from the first bracket in column 



4, and so on till the cycle is complete. The symmetry of the curves is shown 

 by the similarity, for corresponding currents, of the magnetometer readings in 

 the first brackets in columns 4 and 5, and the second brackets in columns 3 and 4. 



