Cryophorus

Instrument contrived by Wollaston, in which water may be frozen by its own evaporation. It consists of a gla tube bent twice at right angles and having a bulb at each end. It contains enough water to partly fill one of the bulbs; the rest of the space is occupied by water vapor only. If the empty bulb be placed in a freezing mixture, the vapor within is condensed, and the water in the other bulb evaporates so rapidly that it freezes. IMG:content-1045.jpg:[graphic] IMG:content-1046.jpg:[graphic]