526 



Bulletin 316 



Heating the air 



The most practical, efficient, and economical method yet devised for 

 protection of large areas is the direct addition of heat by means of numerous 

 small fires properly distributed over the area to be protected. 



For the fanner who desires to protect the farm orchard, this method 

 is offered as neither difficult nor expensive. However, it does require 

 foresight and careful preparation. The fuel to be used must be on the 

 ground and ready for instant use. Moreover, it must be dry, so that 

 fires may be started quickly when the temperature approaches the point 



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Fig. 142. — Orchard owned by J. G. Gore, Medford, Oreg. Crop, valued at $1,000 

 per acre, has been saved Jour years in succession ly the use of old rails for 

 fuel purposes 



of danger. A small investment in an alarm thermometer will obviate the 

 inconvenience of remaining up at night to watch for the time when the 

 fires must be started. These thermometers are constructed to ring an 

 alarm bell when the temperature approaches the danger point. The alarm 

 thermometer should be located in the coldest part of the orchard and set 

 to ring the bell when the temperature is still a few degrees above the point 

 of danger, so as to give time to get the fires started. 



Wood, coal, and oil are the fuels in use, and the choice must depend 

 on local price and supply. 



• Wood. — For the general farmer in New York who wishes to protect 

 merely the farm orchard, open wood fires probably are the most economical. 



