HORTICULTURE 93 



ous small fires well distributed. The small fires do not necessarily 

 change the direction of the air draft, the object being to warm up 

 the draft as it is pressed down from above by the settling of the 

 colder air, and thus avoid the forming of cold spots or pools. Above 

 the danger point the upper air strata are warmer, and usually a few 

 degrees of rise in temperature is all that is necessary for safety. An 

 oil heater is so arranged that the heat may be increased or diminished 

 at will. There are larger heaters that hold 6 gallons of oil and burn 

 thirty-five hours, but the medium size is deemed best for all practical 

 purposes. 



An oil heater can be more easily and quickly filled and lighted 

 than a coal heater. Crude oil has been furnished in tank lots at 

 about 4% cents a gallon and it makes a quick and excellent fire and 

 an intense heat. It is a fuel that will require little or no attention 

 after lighting, but gas oil is considered far better. By using oil one 

 man can care for 3 to 5 acres for four hours, and this is about as long 

 as it is customary to use a heater at any one time. One hundred oil 

 heaters are used to the acre and they can be made to raise the tempera- 

 ture from 10 to 15 degrees. These heaters range in price from 15 to 

 25 cents apiece. The fire can be easily extinguished; the heater is 

 perfectly adjustable and can be closed so that 4 quarts of oil will burn 

 twenty-four hours, or the oil can burn like a bonfire and be con- 

 sumed in two hours. 



Heaters may not be necessary, but if needed will be needed very 

 badly and very quickly. Any one who has 10 acres of orchard lo- 

 cated in the frost belt can afford to use a carload of oil. This oil may 

 be stored in the orchard in iron tanks or in cisterns made of cement. 

 The tanks cost about $75 each and the oil may be saved from year to 

 year if not used. Crude oil has its objections. A disagreeable, greasy 

 soot is produced by it which settles on trees, buildings, outbuildings, 

 and even on the inside of buildings. 



Prevention of Frost Injury Possible. From the abundance of 

 testimony already obtained from reliable sources in various parts of 

 the country, it is safe to say that the prevention of frost injury to 

 fruit crops has passed the experimental stage and has become a well- 

 established fact that can not be controverted or lightly passed by. 



Many thrilling frost fights have occurred in Colorado. In 1908 

 two men saved large crops on the heated half of their places and lost 

 them on the half not heated. This was a practical object lesson to 

 fruit growers, who as soon as they saw what had been done investi- 

 gated the matter thoroughly, and the growers at Canyon City ap- 

 pointed an orchard-heating committee, the first in existence. With 

 $1,000 at their disposal they zealously made experiments to deter- 

 mine just what could be expected in the way of raising the tempera- 

 ture and what the cost would be. For six months these experiments 

 were tried with every sort of fuel and the various market devices for 

 burning it. After an extensive investigation the committee unani- 

 mously recommended oil as fuel, it being as cheap as any other and 

 the fires more easily obtainable. It is said that in 1909 there were 

 orchard heaters in every fruit section in Colorado, and in some sec- 



