Properties of the Alloys of Iron and Aluminium. 127 



The values of the induction obtained in the two sets of 

 experiments are given below. 



Ballistic Method. 



Balance Method. 



H. 



B. 



H. 



B. 



097 



644 



0-52 



160 



1-24 



1,285 



0-92 



553 



1-49 



1,870 



1-30 



1,421 



1-85 



2,990 



1-56 



2,190 



2-20 



4,050 



1-81 



2,895 



2-70 



5,230 



217 



3,905 



3-90 



7,230 



2-50 



4,730 



4-69 



8,170 



3-13 



5,960 



5-08 



8,470 



3-84 



7,075 



7-82 



10,850 



4-76 



8,150 



18-80 



14,230 



5-40 



8,790 



2480 



15,150 



11-38 



12,690 







12-87 



13,020 







2650 



15,230 



These results are plotted in fig. 4, the ballistic reading 

 being indicated thus O, and the balance readings thus x. 

 It will be seen that the two series of results agree with one 

 another within the limits of experimental error. 



Fig. 4. 



Eddy Currents. — As the rings used in the experiments 

 were not laminated, the question of the influence of the eddy 

 currents set up in them on reversing the primary became an 

 important one. 



In J. J. Thomson's Recent Researches, the case of a cylinder 

 placed in a uniform magnetic field which is suddenly destroyed 



