in chemistry, the act of drawing off the spirituous, aqueous, oleaginous, or saline parts of a mixed body from the groister and more terrestrial parts by means of fire, and collecting and condensing them again by cold. The end of distillation is of two kinds: the first, and by far the most general, is for the separation of some acquired bodies from others with which they were mixed, as in the case of vinous and volatile spirits, and essential oils: the other is for the quicker and more effectual combination of such bodies, whose mixture is assisted by a boiling heat, as in the case of spir. nitr. dulce. See Chemistry.

The method of distilling malt-wash, or a fermented mixture of meal and malt, for spirit. Fill two thirds of a still, first moistened by the steam of boiling water, with malt-wash; immediately clap on the head, and let it down; there will soon run a spirituous inflammable liquor. Thus is obtained what the malt-distillers call a malt low-wine; what comes over after the spirit falls off from being proof, is called faints. This experiment may be rendered general, with slight variation; for if any wine, beer, or fermented liquor from sugar, treacle, or fruits, &c. be thus treated, it affords a spirit differing only according to the nature of the subject; but none of them will afford the least inflammable spirit without a previous fermentation. The requisite cautions for success are, 1. That the fermentation be well performed, 2. That it be gently distilled, with a soft well regulated fire, 3. That the groister oil, apt to rise along with the spirit, be let out by flannel under the nose of the worm. These cautions observed, the low-wines will be pure and vinous.

The method of distilling the lower wines into proof spirits for sale. The lower wines of the last process, distilled in a bath-pan, give a higher rectified spirit than before, which being let down with fair water to a certain size or standard, called proof, is what the malt-distillers understand by proof-goods, or their rectified malt-spirit.

The inconveniences of this art, on account of the many large vessels required, which increase the labour and price of the commodity, might perhaps be remedied by the introduction of a new art, subservient to the malt-distillers, and confined to the boiling down the malt-wort to a rob; wherefore it were to be wished, that those who were skilled in this branch of distillation... lution would try whether a spirit superior to that of treacle may not be procured from the rob of malt, prudently prepared and fermented. See Chemistry.

Distinct base, in optics, is that distance from the pole of a convex glass, in which objects beheld through it appear distinct and well described; so that it is the same with the focus. See Optics.