Action of a Magnet on Chemical Action. 47 



course acids which liberated it would have no action. But it 

 is useless to theorize blindly without further experiment ; and 

 we are drawn off by other fields of research. 



In this Journal for 1886, (1. c.) Professor E. L. Nichols has 

 investigated the action of acids on iron in a magnetic field. 

 He remarks that the dissolving of iron in a magnetic field is 

 the same as removing it to an infinite distance and hence the 

 amount of heat generated by the reaction should differ when 

 this takes place within or without the magnetic field. Had he 

 calculated this amount of heat due to the work of withdrawing 

 it from the field, he would probably have found his method of 

 experiment entirely too rough to show the difference, for it 

 must be very small. He has not given the data, however, for 

 us to make the calculation. The results of the experiments 

 were inconclusive as to whether there was greater or less heat 

 generated in the field than without. 



In the same Journal for December, 1887, he describes ex- 

 periments on the action of the magnet on the passive state of 

 iron in the magnetic field. In a note to this paper and in 

 another paper in this Journal for April, 1888, he describes an 

 experiment similar to the one in this paper but without our 

 theory with regard to the action of points. Indeed he states 

 that the ends of his bars acted like zinc, while the middle was 

 like platinum, a conclusion directly opposite to ours. The 

 reason of this difference has been shown in this paper to be 

 probably due to the currents set up in the liquid by the 

 reaction of the magnet and the electric currents in the liquid. 



In conclusion we may remark that our results differ from 

 Professor Nichols in this : First, we have given the exact 

 mathematical theory of the action and have confirmed it by 

 our experiments, having studied and avoided many sources of 

 error, while Professor Nichols gives no theory and does not 

 notice the action of points. Secondly, our experiments give 

 a protective action to the points and ends of bars, while 

 Professor Nichols thinks the reverse holds and that these are 

 more easily dissolved than unmagnetized iron. 



