No. 4.] COLD STORAGE. 227 



box, upon which an extra effort had been expended to have 

 it air-tight. Improvements in the style and construction of 

 the common refrigerator followed in quick succession, and 

 its evohition is seen to-day in that system known as cold 

 storage, by means of which we have, in the way of perishable 

 products, all things at all seasons of the year. As an eco- 

 nomic measure, the system of cold storage is receiving from 

 the business and commercial world great attention, and, 

 taking the country through, millions of dollars have been 

 employed in the esta])li8hment of plants. It is the cold 

 storage room of the average market, the packing house and 

 the wholesale store that enables the owner to keep sound, 

 sweet and free from taint dairy products, eggs, fruit, all 

 kinds of meat and indeed all perishable products. So exten- 

 sive and general has become the use of ice for the preserva- 

 tion of perishable products that it can be said that in these 

 days no market, grocery or fruit store is without its great re- 

 frigerator or cold storage room ; and when one realizes the 

 necessity of this provision, the wonder is, how the world 

 ever got along without its ice supply. So great and impera- 

 tive has become this need of ice, and in such enormous quan- 

 tities, that, cheap as it is as a commercial commodity, and 

 effectual as it may be in lowering the temperature of a given 

 space, this present-day business life has demanded something 

 still better, and, under certain conditions, still less expen- 

 sive. As in practically all instances where a real necessity 

 has existed for some improved method to conserve the wants 

 of man, science has devised that better way, so in the case 

 of refrigeration, has science found a means by which man 

 may create cold without the aid of natural causes or influ- 

 ences, and so perfectly and economically that the artificial 

 means is to be preferred, under certain circumstances, to the 

 use of ice, as by these systems a greater degree of cold or 

 refrigeration is secured than is possible with natural ice. 

 The development of these various methods for creating arti- 

 ficial cold or refrigeration has called into use the highest and 

 most abstruse knowledge the world possesses of heat trans- 

 fers, and the action of compression, expansion and absorp- 

 tion. To give and explain all the details and principles of 

 these different systems is utterly impossible in a paper like 



