Note 390 — ARTIFICIAL ICE. COOLING LIQUORS.

[There is no question that this refrigeration is caused by the evaporation of a portion of the water, whereby a very large quantity of heat becomes latent in the vapour. A clear serene sky being necessary for the success of the production of the ice, would tend to show that the further loss of heat by radiation, which always ensues to a great extent at nights, when the sky is clear, is necessary.]