MINERALOGY. 165 



the length of ninety-eight yards, by which 

 means . JV*W4 grain becomes vifible to the 

 naked eye. 



4. Its foftneis comes neareft to that of lead, 

 and confequently it is but very little elaftic. 



5. It is fixed and unalterable in ^air- water, 

 and fire, becaufe it does not eafily- qitit its 

 phlogiiton •, its liquid menflruum (7 ) be- 

 ins only made bv art. 



It has, however, according to Hom- 

 iberg's experiments, when expofed to 

 Tfchirnhaufen's burning- glafs, been found 

 partly to volatilife in form of fmoke, 

 and partly to fcorify : But this wants to 

 be farther examined. It is alfo faid, 

 •that gold in certain circumftances, and 

 by mean: of certain artifices in electri- 

 cal experiments, may be forced into glafs ; 

 and that on this occafion it becomes white, 

 leaving a black daft behind it •, which, if 

 fo, confirms certain other chemical expe- 

 riments; viz, That gold Can, together 

 with its colour, lofe fome thing of ks phlo- 

 gifbon,- and yet .retain its heavmefs, ducti- 

 lity, &c. 



6. When melted, it reflects a blueim greeh 

 colour from its furface. v : 



7. It diflblves in aqua regia ? which is com- 

 pofed of the acids of fea-fak' and nkre •, but 

 not in either aione, .rpor'iri" any other foiu- 

 tion of fait or acid whatfoever. 



8. When mixed with a volatile alcali and a 

 little of the acid of nitre, by means of 

 precipitation out of aqua regia, it burns 

 off quickly, in the leaft degree of heat, 

 with a flrong fulmination. 



M 3 9. It 





