542 
ON THE MEASUREMENT OF THE MAGNETIC PROPERTIES OF IRON. 
The simultaneous equation method referred to above is more generally stated as 
follows:—^Let the dissipation of energy e be expressed by an equation of the form 
e = AF + BF + &c. Then, if, by proper experiments, the curve expressing e in 
terms of I be determined, the values of the constants K, B, &c., and a, &c., can be 
determined from the curve by taking a sufficient number of corresponding particular 
values of e and I from the curve to form the requisite number of equations. Experience 
shows, however, that it is difficult to obtain the experimental curve with sufficient 
accuracy. In the particular case given above, the results were neither sufficiently 
numerous nor sufficiently accurate for the purpose, and the conclusion arrived at is 
undoubtedly wrong.—T. G.] 
