_a._ From ACETATE OF COPPER:——AROMATIC V.†; SPIRIT OF VERDIGRIS†; SPIRITUS VEN′ERIS†, L.; ESPRIT DE VENUS, Fr.; ACIDUM ACE′TICUM, (Ph. L. 1787.) _Process._ Carefully dry crystallised verdigris (diacetate of copper) by a very gentle heat, and introduce it into a large stoneware retort (see _engr._), the bottom of which has been previously coated with a mixture of clay and horse-dung, to render it more capable of standing the fire. Next place it in a suitable furnace, and connect it, by an adapter, with 3 or 4 double tubulated globes, the last of which must be furnished with a vertical tubulature, to which a double Welter’s safety-tube should be adapted; the other end being immersed in a basin half-filled with distilled vinegar or water, while the funnel portion communicates with the atmosphere. Then place each globe in a basin of water, kept cool by a stream constantly passing through it; and cover the upper portion with cloths kept continually wet with cold water. After 15 or 20 hours, fire may be applied, and must be so regulated that the drops follow each other with considerable rapidity from the end of the adapter, whilst the bubbles of air cause no inconvenience at the other end of the apparatus. If otherwise, the fire must be damped a little. The operation should be continued, and the fire gradually increased, until vapour ceases to come over, known by the globes gradually cooling, notwithstanding the heat of the furnace. The operation being concluded, the whole may be allowed to cool, and the acid collected preparatory to rectification. This may be effected in a similarly arranged apparatus, except that it must be wholly of glass; and the retort should not be much more than half-filled. The operation must now be very carefully conducted, and discontinued before barely the whole of the acid has distilled over; as the last portion is apt to injure the flavour and colour of the rest. The first portions which come over are very weak, and should be kept separate, until the sp. gr. reaches to about 1·372, when the receiver should be changed, and the product collected in separate portions, as noticed below.