[ ^84 ] 



The particles of iron attradl each other more forcibly than 

 thofe of any other known fubftance. This appears by its cohe- 

 fion, hardnefs, elafticity and infufibility, in each of which pro- 

 perties, or at lead in the combination of moil of them, it 

 exceeds all other known bodies. 



Hence a magnet attracts iron when within the fphere of its 

 acflion, by forcing, in virtue of its attractive power, a certain 

 proportion of its integrant particles into a difpofition and ar- 

 rangement fimilar to that of its own. For in this cafe it exerts 

 a double attraiflive power, that of the particles of iron to each 

 other, which we have feen to be the greateft of all others, and 

 that of cryflalizing bodies, which we have alfo feen to be inde- 

 finitely great. 



The cryftallzing power being at once attracSlive and repuljive, 

 according to the direction of the furfaces, (No. 6.) hence we fee 

 that one part or end of the magnet muft jepel that which the 

 other has attradled, as long as the fame difpofition of parts 

 remains. 



The difpofition of parts in a particular magnet, being fimilar 

 to that which obtajns in the great internal general magnet, ex- 

 tends in the diretSlion of from North to South. Hence magnets, 

 when at liberty to move with a certain degree of freedom, and 

 iron, when a fuflicient number of its particles are arranged in 



that 



