326 H. R. Hatnley and A. L. Ross iter : 



The most interesting of these are given by Wilson and others^ 

 Watson,"^ and the manufacturers, Sankey and Sons."' 



Som,e interesting experiments on an alloy very closely allied 

 to " Stalloy '" are given by Barrett, Brown, and Hadfield"', and 

 by Baker .'^ 



The object of the present research was to investigate the 

 nuignetic properties of " Stalloy,'' not only with direct cur- 

 rent, but also with alternating currents of varying frequencies, 

 quencies. 



The experiments have been divided into three divisions: — 



(1) Statical tests. 



(2) Effect of variation of frequency on magnetic hysteresis. 



(3) Eft'ect of annealing upon each of the above. 



The usual statical experiments were made for inductions ex- 

 tending up to about 14,000. From these results were cal- 

 culated the hysteresis losses and Steinmetz coefficients using as 

 exponent in the usual formula the value 1.6 which was found to 

 be approximately correct for this substance. The determina- 

 tion of these coethcients is important as from their values we 

 are able to separate the hysteresis from the total loss in each 

 of the alternating experiments. 



The tests were made upon two rings as nearly alike as 

 possible, one annealed, the other unannealed. 



The alternate current experiments were divided into three 

 series, of periods .07, .035. .0:^ respectively. In each of these 

 the period and wave form of the nuignetizing current were kept 

 as nearly as possible constant as the induction density in- 

 creased. The expressions for the amplitude and phase both of 

 H and B are given in the tables which follow. 



From these expressions, for each pair of associated waves of 

 H and B was calculated the total loss per c.c. per cycle (I). 



This was found to follow fairly well a formula proposed by 

 Lyle^ for total loss in iron, namely : — 



1 Wilson, Winson and O'Dell. Proc. Roy. Soc. Lend., 1908, vol. lx\x, 



•2 Watson. Klectrician, vol. Ix., p. 4. 



3 Article "Stallov." Electrician, vol. Iviii., p. 692. 



4 Barrett, Brown and Handfield. .J.I.K.E., 1902. 



5 Baker. J.I.E.E., December, 1904. 



