—that is, produces a shining flame. Pliny says, still more decidedly, that the Falernian wine, the product of the Faustian field, is the only wine that can be ignited "on contact with a flame"; a thing that happens with some wines very rich in alcohol. These are common phenomena, accidental observations made in the course of sacrifices and festivals which served as the beginning of the discovery. But there had to be many intermediate steps. Among them was this experiment, an amusing trick in physics, doubtless devised by some prestidigitator, which is explained in a Latin manuscript in the Royal Library of Munich: "Wine can be burned in a pot, as follows: Put white or red wine in a pot, the top of the pot being raised and having a cover with a hole in the middle. Having heated the wine till it begins to boil and the vapor comes out through the hole, put a light to it. The vapor will at once take fire and the flame will last as long as it comes out." But alcohol was not isolated by the ancients.
Distillation, or a method of separating the inflammable principle from wine, had to be discovered before a further knowledge of alcohol could be gained-. This process passed through several stages. It also started from common observations. When water is heated in a vessel, its vapor condenses on the walls of surrounding objects, and especially on the cover of the vessel; this can be observed by every one, in domestic economy, on the covers of soup dishes, of kettles, and of tea and coffee pots. Aristotle mentions the fact in his Meteorologica. "Vapor," he says, "condenses under the form of water, if we take pains to collect it." He speaks in another place of a less usual observation, which was probably likewise accidental, and which has been extensively applied in our own time. "Experiment has taught us that sea-water when converted into vapor becomes potable, and the vaporized product, when condensed, no longer resembles sea-water. . . . Wine and all liquids, when vaporized, turn into water." It appeared, then, according to Aristotle, as if evaporation changed the nature of the vaporized liquids and reduced them all to an identical condition—that of water. This change was conformable to the philosophical ideas of the author, wine and sea-water being reduced to the same condition of water, the principle of liquidity, which was regarded by the ancient philosophers as one of the four fundamental elements of things.
Aristotle's remarks on sea-water soon gave the suggestion of a practical process mentioned by Alexander of Aphrodisias, one of his earliest commentators, about the second or third century a. d. According to that author, sea-water was heated in brass kettles, and the water that condensed on the covers was collected for drinking. This was the germ of the industry of the distillation of sea-water, which is practiced now on a large scale on board of ves-
