CHAPTER XXIII 

 COLD STORAGE AND BUTTER FOR STORAGE PURPOSES 



History of Cold Storage. — From early pioneer da}'s the people 

 had a knowledge of the fact that by placing perishable food 

 products where the temperature was low the}- could keep them 

 much better. Many of the early settlers discovered that there 

 was a zone aljout 6 to lo feet below the surface of the ground 

 where the temperature was low. Hence they dug holes in the 

 ground in which to keep various kinds of food products. Later, 

 ice was used in various ways to lower the temperature. It was 

 discovered that the lower the temperature, the better the food 

 products would hold their flavor. 



Refrigeration, as we have it to-day, is the result of a gradual 

 evolution as to both process and efficiency. Coohng by means 

 of ice was practiced by the ancients. We read that the monarch, 

 Nero, had ice-houses built in Rome for the storing of natural ice. 

 The cooling effect obtained through dissolving certain salts was 

 recognized and made use of, as far back as 1762, by Fahrenheit, 

 the inventor of the thermometer that bears his name. Salt- 

 and-ice mixtures have been used for many years for refrigerating 

 purposes, including the making of ice-cream, etc. In what is 

 known as the " Cooper System " of refrigeration, ice and calcium 

 chloride are used. Under this system the temperature of a well- 

 constructed refrigerator can be maintained at 20° F., or below. 



About 1845, -Dr. Gorrie of New Orleans invented a cold-air 

 refrigerating machine. Under his system the air is compressed 

 but is n(it condensed to a liquid; hence it is not so practical as 

 the more modern s}'stems. y\t one time it was used extensively 

 on ships on acc(junt of the absence of obnoxious gases. This 

 s}stcm, while mechanical, dilTers from those here classed under 

 that head. 



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