of the Pyrites. 339 



for the crude, not above three ; in regard the earth 

 burnt-to adheres fo firm to the lead, that, if neve r 

 fcraped off, the lead mud needs melt. Now this 

 lie, after all the vitriol is mot and removed, the 

 alum-boiler takes to his hut, pumps a water there- 

 on holding metallic particles, and adds a lie of 

 wocd-afhes, whereby the green vitriolic colour is 

 difcharged, and the white colour of alum procured ; 

 it is boiled over again for twenty-four hours in lead- 

 pans, and afterwards fuffered to cool and moot ; then 

 the alum is fined and done: the remaining lie is put 

 into a large vefTel, and after ft anding for eight days, 

 it concretes as a cryftal into the figure of the vef- 

 fels, and afterwards is broke in pieces, and is fale- 

 able, or fit for the market. There pafs at lead be- 

 tween five and fix weeks, before a vefTel which holds 

 about eighteen centners, can be filled with alum - 9 

 and when boiled in harvefl or wet weather, or left 

 too long in the vefTel, it generally turns of a fome- 

 what greenifh cad *. 



II. To the boiling for Vitriol. 



At the fulphur-works there is generally a vitriol- 

 ivcrk too, as the bnrnt pyrites is well fitted for that 

 purpofe ; though there is alfo a vitriol boiled from 

 a pyrites j from which never any fulphur was made. 

 Such a work requires a lead-pan feven feet long, fix 

 feet wide, and about two feet deep, weighing be- 

 tween twenty-four and twenty-fix centners ; then 

 e lie- trunks, eleven kct iquare, and two feer 

 high. From the burnt fulpbur -pyrites , which give 

 or refolve in twelve weeks time, there are ninety- 

 fix centners run into one trunk, and there lixiviated 

 with water, and the lixiviated water collected in one 



Z 2 vefTel, 



* Leopold! re'atio hifiorka de itincrc fuo fuccico. An„ ijQ-j, 

 a4 Di WMdvw.rdu.m, p. S4 ieo. 



