Chap. 1 8.] Perfect and imperfeft Metals, &t. 113 



contact with air, and are three in number, filver, gold* 

 and platina : the other metals are calcined in thofe cir- 

 cumftances, and are called imperfect. It will eafily 

 be underftood that thefe differences merely indicate 

 different degrees of attraction for oxygen ; and as in 

 this refpect, as well as in regard to malleability, there 

 are numerous gradations among the metals, it will 

 be neceffary to treat feparately of each metal as a 

 diftinct fubftance. I (hall begin with fuch metals as 

 have mod refemblance to the earths, and are there- 

 fore called femi- metals, and conclude with thofe which 

 have the metallic properties in the higheft perfection. 



Thofe metallic bodies with which we are at prefent 

 acquainted} and which we can reduce to the metallic of 

 reguline (late, are the following feventeen : 



j. Arfenic. 



2. Molybdeha. 



3. Tungftein. 



4. Manganefe. 



10. Iron. 1 -3 



11. Tin. ! j| 



12. Lead. \. 



13. Copper. 



5. Nickel. 14, ?vlercury, 



6. Cobalt. 15. Silver. 



7. Bifmuth. 

 8i Antimony. 



1 6. Gold. 



17, Platina, 



9. Zinc. 



Of thefe the nine firft are called ferni-metals* from 

 defeft of malleability; the five following imperfect 

 metals, from their being calcineable by heat and air 9 

 and the three laft, perfect, from their capacity of re - 

 fiMing the action of heat and air without change. 



It is neceflary, however, to remark, that to the above 

 lift of nine, late difcoveries have added four new femi- 

 metals, viz. uranite, fylvanite, titanite, and mena- 

 Chanite, of \vhich I mall afterwards treat in a diftinct 

 chapter. 



Metals exift in a (late of nature in four different 

 forms. 



VOL. II. I i. The? 



