or ACETITE OF COPPER. See that article, Encycl where an account is given of the process by which verdigris was long manufactured. A different, and more economical process, however, has for some years been practised in Montpellier, which is worthy of notice, because it may be adopted in this country by substituting the husks of gooseberries or currants for those of grapes.

In the manufacture of verdigris, the materials are copper and the husks of grapes after the last pressing. The copper is formed into round plates, half an inch in thickness, and from twenty to twenty-five inches in diameter. Each plate, at Montpellier, is divided into twenty-five laminae, forming almost all oblong squares of from four to six inches in length, three in breadth, and weighing about four ounces. They are beat separately with the hammer on an anvil to smooth their surfaces, and to give the copper the necessary consistence. Without this precaution it would exfoliate, and it would be more difficult to scrape the surface in order to detach the oxygenated crust. Besides this, scales of pure metal would be taken off, which would hasten the consumption of the copper.

The husks, which should not be too much pressed, are first made to ferment by being put into close vats, and the fermentation is generally completed in three or four days. The time, however, must vary according to the temperature in which they are kept, and other circumstances. Whilst the husks are fermenting, a preliminary preparation is given to the copper plates. This consists in dissolving verdigris in water in an earthen vessel, and rubbing over each plate with a piece of coarse linen dipped in this solution. The plates are then immediately placed close to each other, and left in that manner to dry. Sometimes the plates are only laid on the top of the fermented husks, or placed under those which have been already used for caulking the copper to oxidise. It has been observed, that when this operation has not been employed, the plates grow black at the first operation, instead of becoming green. It is not, however, necessary to those which have been once used, and are to be used again.

When the plates are thus prepared, and the husks have been brought to ferment, the workmen try whether the latter are proper for the process, by placing under them a plate of copper, and leaving it buried there for twenty-four hours. If the plate, after this period, is found covered with a smooth green crust, in such a manner that none of the metal appears, they are then thought fit for being disposed in layers with the copper. On the other hand, if drops of water are observed on the surface of the plates, the plates are said to sweat, and it is concluded that the heat of the husks has not sufficiently subsided. They consequently defer making another trial till the next day. When they are assured that the husks are in a proper state, they form them into layers in the following manner:

The plates are all put into a box, which, instead of having a bottom, is divided in the middle by a wooden grate. The plates disposed on this grate are so strongly heated by a chafing dish placed under them, that the woman employed in this labour is sometimes obliged VERDURIS, to take them up with a cloth, in order that she may not burn her hands. As soon as they have acquired that heat, they are put into jars in layers with the husks. Each jar is then closed with a covering of straw, and left to oxidate. Thirty or forty pounds of copper, more or less according to the thickness of the plates, are put into each jar. At the end of ten, twelve, fifteen, or twenty days, the jar is opened; and if the husks are white, it is time to take out the plates. The crystals are then seen detached, and of a silvery appearance on their surface. The husks are thrown back, and the plates are put in what is called redia. For that purpose they are immediately deposited in a corner of the cellar on racks ranged on the floor. They are placed in an upright position, one leaning against the other; and at the end of two or three days they are moistened, by taking them up in handfuls and immersing them in water in earthen pans. They are deposited quite wet in their former position, and left there for seven or eight days; after which they are once or twice immersed again. This immersion and drying are renewed six or eight times every seven or eight days. As the plates were formerly put into wine, these immersions were called one wine, two wines, three wines, according to the number of times. By this process the plates swell up, the green is nourished, and a coat of verdigris is formed on all their surfaces, which may be easily detached by scraping them with a knife.

This verdigris, which is called fijel verdigris, mild verdigris, is sold by the manufacturers to people who dry it for foreign exportation. In this first state it is only a patina, 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. These bags are exposed to the air or the sun, and are left in that state till the verdigris has acquired the proper degree of dryness. By this operation it decreases about 50 per cent., more or less according to its primitive state. It is said to stand proof by the knife, when the point of that instrument pushed against a cake of verdigris through the skin cannot penetrate it. White lead may be made by a similar process.

Crystallized VERDURIS is manufactured at Montpelier in the following manner: A vinegar, prepared by the distillation of four wine, is put into a kettle, and boiled on the common verdigris. After saturation the solution is left to clarify, and then poured into another kettle of copper, where it is evaporated till a pellicle forms on the surface. Sticks are then immersed into it, and by means of some packthread are tied to some wooden bars that rest on the edge of the kettle. These sticks are about a foot long, and are split crosswise nearly two inches at the end, so that they open into four branches, kept at about the distance of an inch from each other by small bags. The crystals adhere to these sticks and cover them entirely, forming them selves into groups or clutters, of a dark blue colour, and a rhomboidal shape. Each clutter weighs from five to six pounds. Three pounds of moist verdigris are required for one pound of the crystals; the undissolved residuum is thrown away.