FRUIT STORAGE 



99 



of the superstructure and to carry the enormous loads 

 of the fruit or material stored. Then inside of these 

 structures are placed the other insulating materials to 

 protect the fruit from fluctuation in temperatures. In 

 some instances dead air spaces are used next to the out- 

 side construction, but in most cases they are filled with 

 sawdust or some other loose substance. Then the use 

 of several layers of matched lumber interspaced with 



Fig. 86. APPLYING INSULATIONS 



building paper, air spaces or sheet cork gives a poor 

 conducting power for the heat from the outside. 



The dead air spaces are at the present time being used 

 less than in former years. "While their insulating value 

 is beyond question, yet it has been proved by experiment 

 that it is almost impossible to make the dead air spaces 

 tight enough to prevent leakage or the circulation of 

 air. And where leakage occurs, or moisture obtains en- 

 trance, they rapidly lose in insulating value. Another 



