PROGRESS OF MAGNETISM. 65 



the presence of a material fluid was not indicated 

 by facts of a different kind, such as the spark, the 

 discharge from points, the shock, and its mechanical 

 effects. Thus the belief of a peculiar magnetic 

 fluid or fluids was not forced upon men's minds; 

 and the doctrine above stated was probably enter- 

 tained by most of its adherents, chiefly as a means 

 of expressing the laws of phenomena in their ele- 

 mentary form. 



One other observation occurs here. We have 

 seen that the supposition of a fluid moveable from 

 one part of bodies to another, and capable of accu- 

 mulation in different parts of the surface, appeared 

 at first to be as distinctly authorized by magnetic as 

 by electric phenomena ; and yet that it afterwards 

 appeared, by calculation, that this must be con- 

 sidered as a derivative result ; no real transfer of 

 fluid taking place except within the limits of the 

 insensible particles of the body. Without attempt- 

 ing to found a formula of philosophizing on this 

 circumstance, we may observe, that this occurrence, 

 like the disproof of heat as a material fluid, shows 

 the possibility of an hypothesis which shall very 

 exactly satisfy many phenomena, and yet be incom- 

 plete : it shows, too, the necessity of bringing facts 

 of all kinds to bear on the hypothesis ; thus, in 

 this case it was requisite to take into account the 

 facts of junction and separation of magnetic bodies, 

 as well as their attractions and repulsions. 

 VOL. in. F 



