CHAP. iv.J APPLICATIONS OF THE LAWS OF HEAT. 



387 



One part of ammonia nitrate and one of water give a maximum 

 effect of 15. 



Lastly, three of snow and four of hydrated calcium chloride give a 

 cold of 48. 



The following are some of the apparatus based upon this action : 

 A mixture of pounded ice and salt contained in a pail into which is 

 introduced a vessel with the syrup, juice, or cream to be frozen, or, 

 according to the usual expression, to be turned into ices, is one of the 

 simplest of these machines It is called the ice-pail (Fig. 266). 



Fm. 2(>9. Family ice-machine. 



Figures 267, 268, and 269 represent ice-machines for family use, all 

 constructed and based on the principle that the cold produced by 

 solution, which is made available, either by the movement of a rocker, 

 or by a rotatory movement impressed on the refrigerating liquid by 

 means of a handle and plates arranged in a helix surrounding the 

 vessel containing the water or syrup to be frozen. In the family 

 ice-machine the melting water from the ice drips through the bottom 

 and sprinkles the bottles of wine, which are thus cooled, or as the 

 gourmands say, iced. 



c c 2 



