284 VINEGAR, CIDER, AND FRUIT-WINES. 



crystalline structure, which is, however, also manufactured in 

 Germany and Sweden. 



The first variety is chiefly manufactured in the region around 

 Montpellier, France. The refuse of grapes, after the extraction 

 of the juice, is placed in casks until acetous fermentation takes 

 place. The casks or vessels are covered with matting to protect 

 them from dirt, At the end of two or three days the fermenting 

 materials are removed to other vessels in order to check the pro- 

 cess, to prevent putrefaction. The limit to which fermentation 

 should be carried is known by introducing a test-sheet of copper 

 into the mass for 24 hours ; if, on withdrawing it at the end of 

 that time, it is found covered with a uniform green coating, the 

 proper degree of fermentation is reached. 



Sheets of copper are prepared by hammering bars of the metal 

 to the thickness of about -^ of an inch (the more compact the 

 copper sheets the better), and they are then cut into pieces of 6 

 or 8 inches long by 3 to 4 broad. Sometimes old ship-sheathing 

 is used and cut into pieces of the required size. The sheets are 

 immersed in a concentrated solution of verdigris and allowed to 

 dry. When the materials are all found to be in proper condition, 

 the copper sheets are laid on a horizontal wooden grating in the 

 middle of a vat, on the bottom of which is placed a pan of burn- 

 ing charcoal, which heats them to about 200 F. In this state 

 they are put into large stoneware jars with alternate layers of the 

 fermenting grape lees ; the vessels are covered with straw mats 

 and left at rest. At the end of 10 to 20 days they are opened to 

 ascertain if the operation is complete. If the upper layer of the 

 lees appears whitish and the whole has worked favorably, the 

 sheets will be covered with silky crystals of a green color. The 

 sheets are then taken from the jars and placed upright in a cellar, 

 one against the other. At the end of two or three days they are 

 moistened with water and again placed to dry. This moistening 

 with water is continued at regular intervals of a week for six or 

 eight times. This treatment causes the sheets to swell and 

 become incrusted with increased coatings of the copper salt, 

 which are detached from the remainder of the sheets by a copper 

 knife. The scraped plates are submitted to a fresh treatment till 

 the whole of the copper is converted into verdigris. The salt 



