in the Pyrites. 197 



yellow copper are, with us, held to be one and 

 the fame thing, but among the French, the lat- 

 ter is made from formal zink, and fuch yields no 

 tutia ; and as there is but little of it prepared, 

 there mud be but little demand for it : nor, at out- 

 author's faying, that the tutia arifes not at the fame 

 time Kith the pompholyx -, for, be this as it will, the 

 tutia is derived from the very fame principles with 

 the pompholyx, namely, calamy, and tinges copper 

 yellow. In fhort, tutia, nihilum, cadmia fornacum^ 

 foffile calamy, and formal zink itfelf, agree entirely 

 in principles, though they differ in fcrm and acci- 

 dental appearance. 



This digrefiion from arfenic to zink, cannot be 

 thought difpleafing to the reader, feeing they are 

 the effect of one operation, and, confequently, have 

 an affinity with each other -, and, upon rightly 

 taking the matter, the pyrites, cither from its ful- 

 phur or arfenic, a Ml its to the production of zink : 

 nay, it may be queried, whether, as Charras pre- 

 tended, .1 zink may not be made from arfenic. 

 Befides, I want d to clear up a fet of names, fome- 

 times applied to one thing, fometimes to ano- 

 ther. 



Arfenic, crphnent, realgar, and fandaraca, ftand 

 for t.iing c -, which if not entirely a-fenical, ge- 

 nerally partake considerably of it. Orpiment is a 

 fulp'-.ur-yellow, fla key, arfenical mineral , of which 

 painters, with the aid of indigo, ufually compofe a 

 green. Realgar is an unknown term, with fome 

 denoting the lame thing as arfenicum cryftallinum 

 flauum \ with others, c.rfnicum rubrum, or the 

 common fandarach -, yet it always means fomething 

 in which the arfenic is the principal part, and the 

 fulphur, which, in both the red and yellow, makes 



O 3 the 



