306 Mr HARRIS'S Experimental Inquiries concerning 



velopement is supposed to exist only in one substance : we have 

 now to consider very similar phenomena evinced in the action 

 of one magnet on another, in which case there is a permanent 

 magnetic developement in both substances, a case of magnetic 

 action somewhat more complicated than the former, but which 

 is still susceptible of a similar experimental examination, the in- 

 ductive action being observed to proceed, whether the bodies be 

 permanently magnetic or not, or whether opposed at their similar 

 or dissimilar poles *. We have consequently to investigate the 

 operation of this inductive influence when the bodies under exa- 

 mination have a permanent magnetic developement of greater 

 or less extent. 



43. In order to examine the inductive action of one magnet 

 on another, a magnetised piece of steel be, Fig. 5. was placed un- 

 der the suspended iron x, and the attractive force at a given dis- 

 tance duly noted. A magnetic bar m was then placed under it ; 

 first the similar poles, and secondly the dissimilar poles, being 

 opposed, having previously ascertained the force of the magne- 

 tized steel be at each pole, and made them equal, and having al- 

 so equalized the poles of the magnet m, and ascertained their 

 force. The results obtained from a series of experiments thus 

 arranged, appeared to show in a satisfactory way that the forces 

 acquired or lost by the magnet be, at its superior pole, in conse- 

 quence of the inductive action, were, within certain limits, in the 

 inverse ratio of the distance between the two magnets ; after 

 which the increments or decrements began to diminish. In the 

 following Table, are seen the results of a series of experiments 



* Although by opposing two magnets at their dissimilar poles, we in great mea- 

 sure destroy their permanent magnetism, yet the inductive influence by which this is 

 effected must still be considered as a new force induced in the magnets, since it has 

 been capable of producing a certain effect. 



