206 A SYSTEM OF 



of a pure, and a very rich iron ore : Large veins of 

 the fame ore are likewife found in almoft every 

 province of that kingdom of fuch a nature, that 

 few countries can produce better or richer. 



The magnetical power, with relpecl to its prin- 

 ciples and origin, is no better underftood than 

 electricity, yet fomewhat more with refpec! to its 

 effects. Though both thefe qualities are now con- 

 sidered as different powers, they may perhaps in 

 time be regarded as fomething nearer allied to 

 each other. 



The magnetical power is not innate in the iron, 

 but is collected into it by degrees, which is veri- 

 fied by experiments -, it may be expelled, it may 

 vanifli and gather again, as it were out of the air, 

 fince the natural loadftones for the moil part occur 

 in fmall veins to the day, whilfl deeper, only refrac- 

 tory iron ores are found. There is the fame differ- 

 ence between an artificial magnet of Dr. Knight's, 

 and a bar of fbeel, whether of the fame fhape or 

 not, as between a natural loadfione, and a blackifh 

 blue iron ore ; whence it is ridiculous to infift with 

 a certain author, that no iron ore can be attracted 

 by the loadftone, but what of itfelf contains fome 

 magnetical virtue. 



SECT. CCXVI. 

 The Second Order: 



Se M I-M E T A L S. 



There are but feven femi- metals yet difcovered. 



viz. 

 i. Quickfilver, Mercury, Argentum vivum, 

 Mercurius^ Hydrargyrum. 



This diftinguifhes itfelf from all metals, by 

 the following qualities. a. Its 



