of the Pyrites. 341 



III. To the making of Arsenic. 



Arfenic is made partly from a peculiar pyrites^ or 

 cobald, partly from a fort, amongft which tin- 

 {tone is found, partly from the fmalt-cobald, part- 

 ly alio from the gold and filver holding mijfpickel, 

 or white pyrites ; and all thefe cobalds or pyrites mud 

 previoufly be parted from the barren minerals, by 

 {tamping and warning, and made into a pure jludge, 

 from which afterwards, by means of roalting and 

 burning, the arfenic is forced out in the fume, and 

 catchtd. Formerly, the furnace had one fmall a- 

 perture, by which the fire was kept up, and the 

 jludge ftirred ; was internally about eight feet wide, 

 and iomething longer, and two feet high, like an 

 oven, with an arch over it, and on that a long ho- 

 rizon til palT:ige, or funnel, of mafonry, eighty- 

 eight feet long, of the height of a man, and three 

 feet wide, called the meal funnel ; on the end of ic 

 was erected a pipe for difcharging the fmoke of the 

 wood and the arfenic fume; at proper diftances in 

 the funnel were windows or apertures a foot fquare, 

 which were kt open at taking out the meal. Now, 

 when a roafi-work^ or quantity of jludge ', was burnc 

 in the furnace, after being firft well ftirred, the ar- 

 fenic or fume being retired into the horizontal fun- 

 nel, fell, at length, like a meal, to the bottom, 

 and, in part, adhered thereto. Upon the furnace's 

 cooling a little, the jludge was drawn, and replaced 

 with other, which was roafted and burnt fo long 

 and fo much, 'till all itswildnefs was forced out, as 

 was done to the firft : and thus they proceeded, 'till 

 they were to remove the meal from the long fun- 

 nei, which was done by perfons whofe faces were 

 bound up, efpecially the nofe and mouth, and 



3 had before fwallowed fome bacon: but ac 



Z 3 pref^nt 



