Frost and the Prevention of Damage by It. 



27 



tion. Some fruit growers prevent contact between the bottoms of 

 the heaters and the ground by placing the heaters on small square 

 pieces of board. 



The cost of the larger heaters is so great that it is good practice to 

 give each one a coat of good stack paint at intervals of 2 or 3 years 

 to prolong its life. Mr. Willis S. Jones, of Claremont, Calif., has his 

 heaters thoroughly brushed with a steel brush to remove rust and 

 dirt. Each heater is then placed on an iron grating under which one 

 or two heaters are burning until it is brought to a high temperature, 

 after which the paint is applied hot. 



At the end of each season the heaters usually contain a small quan- 

 tity of a mixture of soot and asphaltum, which sticks to the bottom 



FIG. 12. Continuous records of the temperature inside and outside a heated pear orchard, 

 showing the effect of the firing on the temperature. Five-quart lard-pail oil heaters 

 were used. Note that the temperature in the heated orchard ran about 2 lower than 

 at the check station before the heaters were lighted. 



and is difficult to remove when cold. The usual method of removing 

 this material has been to burn it out with distillate. In doing this 

 accidents often occur and piles of several hundred or more heaters 

 sometimes catch fire, ruining the heaters and endangering surround- 

 ing property. 



At the Bear Creek Orchard, Medford, Oreg., the manager, Mr. B. B. 

 Lowry, has a trench covered with sheet iron on which he treats the 

 empty heaters at the end of the season. A fire is built under the iron, 

 using the residue from the heaters for fuel, which burns fiercely. A 

 large inclined flue carries away the smoke from the fire and creates 

 a draft. The heaters, a dozen at a time, are placed on the sheet iron 



