VOL. XXXIII.3 PHILOSOPHICAL TRANSACTIONS. lOQ 



proach of a foreign fluid, or its egress from the magnet, or some of it at least ; 

 but experiments show, that the magnetic forces are nowise hindered ; or shall 

 these effluvia be much more subtile than the rays of light ? Besides, that this 

 again is but an hypothesis, the above difficulty is not removed : fire is inter- 

 cepted by bodies, and light does not immediately penetrate all bodies; and thus 

 it is with all fluids, they meet with resistance from solids ; but it is not so with 

 the magnetic effluvia, they meet with none from a solid body; and this is the 

 grand difficulty. 



But he takes the strongest argument from the repelling forces of magnets, 

 which are much weaker than the attracting forces, as appears from the experi- 

 ments below ; so that a fluid must necessarily come from without towards the 

 magnet, which meeting the other magnet, impells the one fluid towards the 

 other, and which enters the magnet ; and because the magnetic attraction is 

 much stronger than the repulsion, a greater quantity of the fluid enters into the 

 magnet than passes out from it : whence the magnet must necessarily be soon 

 filled with this fluid, so as to be no longer porous ; nor can it be supposed, that 

 this fluid is emitted from all parts of the magnet, as it were; for, the attraction 

 is in every point of the magnet, but the repulsion is only in the poles. In 

 order to show that the magnetic repulsion is less than the attraction, the follow- 

 ing table contains the experiments, made with the last mentioned magnets. 



Distance. Grains of 



inch. Jin. repulsion. 



1 11 10 



1 10 17 



I 4 17 



I O 24 



10 24 



7 25 



6 234. 



5 274- 



4 29 



1 34 



in the very point of contact 44 



Hence it appears that no proportion can be deduced from these experiments 

 on the repulsion of magnets ; but that magnets are indeed very surprising 

 bodies, of which we hitherto know but very little. 



