334 LATENT AND SPECIFIC HEAT. 



(5.) To three weights of quicklime add one weight of water. 

 The water will be completely solidified in the slaking of the lime 

 with remarkable thermal manifestations. Carts containing quick- 

 lime have been set on fire by exposure to heavy rains. 



525. Change of Bulk during Solidification. 



Most substances shrink in size during solidification ; but 

 a few, such as ice, cast-iron, antimony and bismuth, are 

 exceptions. When melted cast-iron is poured into a mould, 

 it expands in cooling and presses into every part of the 

 mould. The tracings on the casting are, therefore, as clear 

 cut as they were in the mould. A clear-cut casting can 

 not be obtained from lead ; this is one of the reasons why 

 antimony is made a constituent of type-metal. Gold coins 

 have to be stamped ; they cannot be cast so as to produce 

 a clear-cut design. The bursting of pipes by freezing water 

 is a common source of annoyance. 



(.) An army officer at Quebec performed the following experi- 

 & ment : He filled a 12-inch 



shell with water and closed 

 the opening with a wooden 

 plug forcibly driven in. The 

 shell was put out of doors ; 

 the temperature being 

 28 C., the water froze, the 

 plug was thrown about 300 

 feet, and a tongue of ice 

 about eight inches long pro- 

 truded from the opening. 

 In a similar experiment, the 

 shell split and a rim of ice 

 FIG. 253. issued from the rent. 



526. Latent Heat of Vaporization. The 



vaporization of a liquid is accompanied by the disappear- 

 ance of a large quantity of heat, and frequently by a diminu- 

 tion of temperature. There is a change of sensible into 



