198 Of the Arsenic 



the diftinction, is, in the former, fomewhat more > 

 and in the latter, fomewhat lefs in quantity. San- 

 daraca, properly denoting a gum, or rofm, is here 

 alfo applied to a mineral, which is, or appears to 

 be gummy, or fatty. Now, 'tis true, genuine ful- 

 phur is of fuch a nature and form, but by it this 

 laft is not meant, buf fomething arfenical, only 

 combined with fulphur •, and, in fhort, fuch a body 

 as, be it white, yellow, or red arfenic, may, both 

 by a lixivial and acid fait, (which is fomething very- 

 extraordinary) in particular by fpirit of nitre, be 

 changed into a formal gum. 



We are, in the next place, to enquire into the 

 origin of arfenic, or whence it is derived. And (1.) 

 'tis found in the earth fo pure and fnow- white, as 

 fcarce to be rendered more fo by art •, but this is a 

 very rare cafe. So far as I have been able to judge 

 from circumftances, it may lie unobferved by coarfe 

 veins, confifting of pyrites, mijfpickel, mockr-lead, 

 and glitter-, yet the arfenic -pyrites commonly, and 

 in large quantities, breaks among them, and chiefly 

 contains the arfenic. At Friberg we know no- 

 thing of this arfenic, the famples I have either 

 feen, or actually had in my pofTeffion, being only 

 from the mines of Joachimfthal, in Bohemia, 

 where the veins confift, together with red-goldifh 

 ore, both of the fmalt-cobald, and that other black 

 arfenic-ove, of which more by and by, ufually called 

 cobald, but really a kind of pure fly-ftone, or footy 

 arfenic. 



Whether this white, foflile arfenic be an original 

 production, whofe particles, before thus exhibited^ 

 were not arfenic, but firft became fuch in the exhi- 

 bition ; or rather, whether its origination conlifts 

 only in a reparation from another body, wherein 



indeed 



