100 MODERN FRUIT MARKETING 



precaution that is necessary to consider is the water- 

 proofing of the outside walls to prevent moisture from 

 getting into the filler or the papers used on the inside. 

 All of the heavy work, stone and cement, is coated with 

 pitch or some substance to make it impervious to 

 moisture. Each set of material inside is also coated. 

 In addition, from the inside many precautions must be 

 taken to prevent the moisture from collecting on the 

 walls in sufficient quantity to wet the insulating ma- 

 terials. 



Mechanism of Cold Storage. There are two well- 

 recognized systems for cooling down storage houses : 

 (1) Ice refrigeration, and (2) Mechanical refrigeration. 

 The cheaper and most common used material is ice, espe- 

 cially in the Northern states and the smaller houses. The 

 larger storage houses in the big cities or those of the 

 Southern states use mechanical refrigeration. It is difficult 

 to give any estimate of comparative cost because of the 

 wide variation in conditions, labor, cost of material, etc. 

 As a general rule, for small or local cold storage houses 

 ice is considered the cheaper, especially in the Northern 

 states where ice can be manufactured in the winter at 

 a low cost. Farther south it would be necessary to make 

 the ice artificially and the cost would be much greater 

 than for mechanical refrigeration. 



In the larger cities of the East where public storages 

 are common, the mechanical system is used almost ex- 

 clusively and by most operators is conceded to be the 

 cheapest and the most economical to operate. Storage 

 houses, up to 5,000-barrel capacity, will probably be 

 cheaper to cool by ice than by mechanical means, and the 

 smaller plants operated by cooperative organizations are 



