188 



tapped during repeated reversals of its 

 magnetism, there was practically no dissi- 

 pation of energy through hysteresis, and 

 even a very slight mechanical disturbance 

 had some influence in reducing the dissi- 

 pation. In applying this result to 

 dynamos, all that he had said was this : 

 " Hence, in a dynamo, where vibration 

 occurs to a greater or less degree when - 

 ever the machine is running, the energy 

 dissipated through changes of magnetiza- 

 tion is even less than these experiments 

 on still metal would lead us to expect.'* 

 He had meant, in these words, to draw 

 attention to the fact that whatever vibra- 

 tion occurred in the armature of a 

 dynamo would tend to lessen the dissipa- 

 tion of energy, produced by hysteresis 

 below the value measured by his experi- 

 ments on still metal. He had not meant 

 to suggest that any large effect of this 

 kind was actually produced, and in fad 

 he agreed with the author in believing 

 that in a well-balanced dynamo the vibra- 

 tion was not likely to be seriously influen- 



* Phil. Trans. Royal Society, 1885, p. .v.4. 



