Stalloy. 



329 



from a thin annulus cut from one of the actual rings used. 

 The results differed by less than .1 per cent and agreed fairly 

 well with the results of other experimenters. 

 The details of the coils are : — 



No. of laminae 

 Internal diameter - 

 External ,, - - 



Mean thickness (x) 

 Area of cross section 

 Length of magnetic circuit 

 Primary turns 

 Secondary turns 

 Specific resistance at 19° C 

 Specific gravity at 19° C 



Annealed. 



6 

 6.927 cms. 

 9.549 cms. 

 .0757 cm. 

 .5953 sq cm. 

 5J5.87 cms. 

 135 

 10 or 50 

 50320 

 7.58 



Unaniiealed. 



6 

 6.927 cms. 

 9.557 cms. 

 .0739 cm. 

 .5830 sq. cm. 

 25.90 cms. 



135 



10 or 50 



50440 



7.582 



The reduction factor of the galvanometer used in the second- 

 ary circuit was obtained by passing the current from a cadmium 

 cell through a megohm and the galvanometer in series. 



All the resistances used were carefully tested during the course 

 of the experiments, as were also the two standard M coils which 

 were used to determine the absolute value of the magnetizing 

 force. 



The symbols used in the accompanying tables are as follow; — 



T = period = 27r/ci) = -07, "035, "02 approx. 



H = HjUinW + k.^s\n.3{o)^ - (j)-^) + /i-jsin5{u}^ - <f>^) + ] 



B = Bi[sin(a>/ -0) + A,sin3(W -0 - t/^,) + /;5sin5(w/ - 6 - if/,,) + . . ] 

 fxo = Bj/Hi IX = Bo/Hfl. 



U = o-B,, 



g = 



2 id\i\ 



^R.M.S.(^) 



I = Total loss per c.c. per cycle. 

 U = Statical hysteresis loss per cycle. 

 E = Eddy current loss per cycle. 

 I — U — E = Kinetic hysteresis per cycle. 



In Tables I., II., III., are given the analytical results reduced 

 from the series of experiments on the annealed ring, while 



