32 CALORIC. 



when more or less ice is found in them, according 

 to the temperature of the air ; there being more 

 formed in dry and warm weather than in cloudy 

 weather, though it may be colder to the human 

 body. 



Every thing in this operation is calculated to 

 produce cold by evaporation ; the beds on which 

 the pans are placed suffer the air to have a free 

 passage to their bottoms, and the pans, constantly 

 oozing out water to their external surface, are 

 cooled by the evaporation of it. 



In Spain, they use a kind of earthen jars called 

 buxaros, the earth of which is so porous, being 

 only half baked, that the outside is kept moist by 

 the water which filters through it ; and, though 

 placed in the sun, the water in the jar becomes as 

 cold as ice. 



It is a common practice in China, to cool wine, 

 or other liquors, by wrapping a wet cloth round 

 the bottle, and hanging it up in the sun. The 

 water in the cloth evaporates, and thus cold is pro- 

 duced. 



Ice may be produced, at any time, by the eva- 

 poration of ether. Take a thin glass tube, four or 

 five inches long, and about two or three eighths of 

 an inch in diameter, and a two-ounce bottle of 

 ether, having a tube drawn to a point, fitted to 

 its neck. Pour some water into the glass tube, 

 and let a stream of ether fall upon that part of 

 it containing the water, which, by that means, will 

 be converted into ice in a few minutes. If a thin 

 spiral wire be introduced into the tube before the 

 water is poured in, the ice will adhere to it, and 

 may be drawn out. 



