Method of manufaBurhig CryJlalTifcd Verdi grifc. lyi 

 principle, or any peculiar and aftivc eleftricity of the organs. 

 By their afliftance you will be enabled to invent new experi- 

 ments, and to foretell the refult of them, as I have feveral 

 times done, and Itill do daily. If you, however, abandon 

 thefe principles, you will find nothing but uncertainty and 

 contradiction, and the whole will be an inexplicable 

 problem, 



JX. On the Method- of mnnufaSimng Acetat of Copper, Cry- 

 Jlals of Venus, or Crjjlallifed Verdigrife. By J. A. Chap^ 



TAL.* 



\^T1YSTALS of Venus wprc for a long time manufaftured 

 in Holland, but at prefent they are manufatlured at Mont- 

 pellier, with a degree of pcrfeftion wliich renders them 

 preferable to thofe of any other country. The procefs 

 moft generally employed confifts in diflblving verdigrife in 

 vinegar, and evaporating the folution to a pellicle to obtain 

 the cryftals. The vinegar ufed is nothing elfe than four 

 ijinafjc (fpoilt wine) diflilled. In every manufa«Story ther» 

 is therefore an alembic^ in which this weak kind of vinegar 

 is continually diflilled. 



This diftilled vinegar \i put ijrto a kettle, where it is boil- 

 ed on the verdigrife. After faturation the folution is left to 

 clarify, and then poured into another kettle of copper, where 

 it is evaporated to a pellicle. Sticks arp then inmierfed into 

 it, and by means of fonie pack-thread aj-e tied to wooden 

 bars which red on the cdgp of the kettlg, Thefe flicks arc 

 about a foot long, and are fplit crofs-wife nearly two inches 

 ;it the end, fo th;it they open into four branches, kept at 

 about the diftance of aji inch from each other by fmall pegs. 

 The crylials adhere to thefe flicks, and cover them entirely, 

 forming thenifelvcs into groups or cluflers, which prefent 

 'f)U all fi4cs peife<!;l rhombs of a very lively dark blue colour:. 



• J-rom the Ar.iialcs dc Cjiimic, No. 75. 



Each 



