Page:Popular Science Monthly Volume 19.djvu/251

Rh He has submitted to distillation some fifteen or twenty litres, or quarts, of snow-, rain-, or sea-water in the apparatus which is represented in Fig. 1. This apparatus consists of a milk-can, B, which is made to serve as a boiler, in which the liquid to be distilled is put. The vapors disengaged by the heat pass through a worm about thirty feet long, in which they are resolved; thence through a tube incased in a refrigerating envelope, T, which is kept constantly cool by a current of cold water; and are then condensed in the glass receiver, R. The operation is arrested as soon as one hundred or one hundred and fifty cubic centimetres of liquid—which will contain all the alcohol—have been condensed. The resultant liquid is again distilled in an



apparatus similar to the former one, but smaller. The latter operation is arrested when some five or six cubic centimetres of liquid have been condensed in a closed receiving-tube, which takes the place of the receiver R in the former apparatus. The tube is then taken away, and to its contents are added a little iodine and carbonate of soda; on heating it slightly, small crystals are precipitated of iodoform, a substance which could not be produced unless alcohol were present. M. Müntz has verified the results of this process by other test experiments. When distilled water, chemically pure, was heated in the same apparatus, the addition of iodine and carbonate of soda was not followed by any reaction. A second verification was obtained by distilling fifteen litres of pure water, to which one millionth part of alcohol had been added; the addition of iodine and carbonate of soda caused a precipitation of iodoform precisely like that which was