26 THE AMERICAN PEACH ORCHARD 



Mountain districts, a different method, namely, 

 orchard heating. This method depends upon the 

 direct temperature secured by burning the neces- 

 sary amount of fuel in the orchard. Four fuels have 

 been generally used: (a) wood, (b) coal, (c) bri- 

 quettes, (d) oil. 



Where wood is plentiful and cheap, as it is in 

 many sections of the Rocky Mountain states and the 

 west coast, it is prepared in convenient sizes and 

 placed in piles throughout the orchard ready for 

 lighting. When frost is threatened these piles are 

 fired and the blaze kept going by the addition of more 

 wood until the sun warms the air beyond the danger 

 point. 



In many sections coal is available at a low price 

 and can be used in the same manner, except that 

 special fire pots are usually required. These are 

 offered for sale by western manufacturers and serve 

 to burn the coal rapidly and economically. The 

 usual estimate is that where coal can be had at $2 

 to $3 a ton, this method will be more economical 

 than the use of oil at $5 to $6 the 100 gallons. There 

 is a good deal of argument over this point, however, 

 the estimate not being accepted by all fruit growers. 



Briquettes which are not available in many parts 

 of the country, vary considerably in composition, so 

 that their value cannot be easily estimated. They 

 are composed of coal dust, tar, sawdust and other 

 refuse materials made into the size and form of 

 ordinary building bricks. If they have a consider- 

 able proportion of good inflammable material, they 

 will burn well and give a reasonable amount of heat. 

 They are not widely used, and not likely to be. 



The standard fuel for heating is oil. However, 

 there are many different kinds of oil and many 

 grades in the market, and one of the most serious 



