104 AUXlICUL]r(JRAL MU-SEUK 



MANUFACTURE OF VERDIGREASE. 



This article, which is so extensively employed in the 

 arts and manufactures, either as pigment or as a drug 

 used in the process of dying, has become so high in con- 

 sequence of its scarcity, that a mode by which it may be 

 prepared iu this country, on an extensive scale, cannot 

 fail interesting tha painter or the dyer. 



Verdigreasc, properly speaking, is a preparation of 

 copper, made by corroding copper plates with the re- 

 fuse matter of the grape. It is chiefly manufactured at 

 Montpclier ; the vines of Languedoc being very con- 

 venient for that purpose. The author of the Dictiona- 

 ry of Merchandize says, that in the preparation of ver- 

 digreasc of INIontpelier ; " Vine stalks, well dried in the 

 Sun, are put into eathern pots, and upon them wine is 

 poured. The pots being fully covered, the tvine then un- 

 dergoes the acetous fermentation, which in summer is 

 finished in seven or eight days. When the fermentation 

 is sufficiently advanced, the stalks are taken out of the 

 pots, and being by this method impregnated with 

 all the acid formed by the acetous fermentation, the 

 remaining liquor is but a very weak vinegar. The 

 stalks well drained, are put into earthen pots, in 

 alternate layers with plates of copper. The copper 

 is thus left to the action of the vinegar for three or 

 four days, or more ; in which time the plates beccrmc 

 covered with verdigreasc. The plates are then taken 

 out of the pots and left in the cellar three or four days, 

 when they are moistened with water, or with the weak 

 vinegar above mentioned, and left to dry. When this 

 moistening and drying of the plates, has been thrice re- 

 peated, the verdigreasc will be found to have considera- 

 bly increased in quantity." 



The aiK'ients, however, diftered in respect to the process 

 of corroding copper The copper, which was i« plates, 

 shavings, or filings, was immersed in the sour water left 

 after the formation of wine. Sometimes the copper was 

 exposed to the vapour of vinegar, wliich; indeed, instcaxi 



