350 Fruit-growing in Arid Regions 



number of heaters on the windward side of the orchard 

 than an equal number of scattering fires. It has been 

 observed that on a still night the benefit derived from 

 these heaters does not extend far outside the boundaries 

 of the orchard, and many times with a temperature as 

 low as 23 the crop has been a total failure within less 

 than a hundred feet of the last row of heaters when a 

 perfect crop was saved inside the heated area. 



Oil heaters burning a quart of oil per hour and at the 

 rate of 80 per acre should be ample protection in fighting 

 a temperature of 20, and coal heaters burning five pounds 

 of coal per hour should afford the same protection with 

 the same number per acre. Some of the larger heaters 

 consuming more fuel have been recommended as sufficient 

 protection when used as few as forty per acre, but it has 

 been fairly well demonstrated that it is better both for 

 the complacency of the men and sometimes for the orchard 

 to have sixty. If one insists upon using oil burners that 

 will not go through the night without refilling, it might 

 be better to double the number of pots and burn them 

 in two shifts. This would of course add to the expense 

 of equipment, but would enable the grower to handle a 

 large acreage with less help. 



Oil burners may be filled and placed in the orchard at 

 any time after the fruit-buds have advanced far enough 

 to be endangered by sudden drops in temperature. They 

 must be kept well covered to exclude moisture, for this 

 has a tendency to make the oil sputter and boil over. 

 The burners are easily lighted with a torch, using a little 

 waste for a wick. The waste may be thrown on the sur- 

 face of the oil, but it will light more readily and will be 



