the ManufaBuring of Verdigrlfe, *^J 



pofe they are immediately depofited in a comer pf the cellar 

 on flicks ranged on the floor. They are placed in an upright 

 pofition, one leaning againft the other ; and at the end of 

 two or three days they are moiftened, by taking them up ia 

 handfulls and immerfing them in water in earthen pans. 

 They are depofited quite wet in their former pofition, and 

 left there for feven or eight days ; after which they are once 

 or twice immerfed again. This immerfion and drying are 

 renewed fix or eight times, every feven or eight days. As 

 the plates formerly were put into wine, thefe immerfions 

 were called one ivitie, two wineSf three zviTies, according t» 

 the number of times. By this procefs the plates fwell up, 

 the green is nourifhed, and a coat of verdigrife is formed oh 

 all their furfaces, which may be eafily detached by fcraping 

 them with a knife. 



Each jar fumifhes five or fix pounds of verdigrife at each 

 operation. It is then called frefli verdigrife, moift verdigrife, 

 &c. This verdigrife is fold in that ftate by the manufactu- 

 rers to people who dry it for foreign exportation- In this 

 fjrfl flate it is only a pafte, which is carefully pounded in 

 large wooden troughs, and then put into bags of white 

 leather, a foot in height and ten inches in diameter. Thefc 

 bags are expofed to the air or the fun, and are left in that 

 fiate till the verdigrife has acquired the proper degree of dry- 

 nefs. By this operation it decreafes about fifty percent,, more 

 or lefs according to its primitive fxate. It is faid to Hand 

 proof by the knife, when the point of that inllrument puflitd- 

 againft a cake of verdigrife through the fkin cannot pene- 

 trate it. 



The plates of copper which have been already ufcd aiie 

 again employed for the fame operation, till they are almofi 

 completely confumed, Inftead of heating them arlificially, 

 as above mentioned, they arc fometimcs expofed only Ui thfi 

 fun. The fame plates will ferve fometimes for ten years, but 

 •Jiey are often worn out in two or three. This, howccr, 



^cpeu4$ 



