What is "cryophorus"

cryophorus \cry*oph"o*rus\ (kr[-i]*[o^]f"[-o]*r[u^]s), n. [NL., fr. Gr. kry`os icy cold, frost + fe`rein to bear.] (Chem.) An instrument used to illustrate the freezing of water by its own evaporation. The ordinary form consists of two glass bulbs, connected by a tube of the same material, and containing only a quantity of water and its vapor, devoid of air. The water is in one of the bulbs, and freezes when the other is cooled below 32[deg] Fahr.

A cryophorus is a glass container containing liquid water and water vapor. It is used in physics courses to demonstrate rapid freezing by evaporation. A typical cryophorus has a bulb at one end connected to a tube of the same material. When the liquid water is manipulated into the bulbed end and the other end is submerged into a freezing mixture (such as liquid nitrogen), the gas pressure drops as it is cooled. The liquid water begins to evaporate, producing more water vapor. Evaporation causes the water to cool rapidly to its freezing point and it solidifies suddenly.