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appropriation to Iron. 



It has of old been obferved that the magnetic phasnomena 

 were peculiar to iron, and the reafons why they are fo have been 

 already affigned, but of late fome femi-metals have been obferved 

 to partake of thefe properties, as Nickel, Kobalt and Manganefe ; 

 this has been thought to arife from a mixture of ferruginous par- 

 ticles from which they can be fcarcely freed, and with refped to 

 Manganefe, and in many cafes of the others alfo, this feems to 

 hold true ; but with refped to Nickel, and in fome inftances of 

 the others alfo, the magnetic properties they difcover feem to me 

 to proceed from their great attradion to iron, particularly when 

 their particles are duly arranged, for then they are expofed to the 

 power of the great general magnet, which ads on them in pro- 

 portion to this arrangement and their affinity to iron. 



Of Inclination and Declination, 



These phaenomena, which are fo different in different parts of 

 the globe, and even in different feafons and hours of the day, 

 not being as yet noted with fufficient certainty and precifion, I 

 fhall for the prefent decline entering into their explanation. 



