FROST 



FROST 



1287 



leaving behind anything but a little soot; but the oils 

 with an asphaltum base do not. For this reason it is 

 found necessary to remove the asphaltum base in so 

 far as is practicable. Asphaltum does not burn readily 

 in a simple smudge-pot, and, therefore, remains 

 behind after the lighter oil has burned. Upon cooling, 

 it becomes very hard, and reduces the capacity of the 

 pot for future fillings. The best oil for orchard-heating 

 purposes is one of approximately 20 Beaume test, 

 considering the matter of cost as an item. A lighter oil 

 up to 32 Beaume may be used, but being lighter, it 

 will burn more rapidly and reduce the effective burn- 

 ing time of the orchard-heater. 



The orchard-heater. During recent years, large num- 

 bers of types of orchard-heaters have been placed 

 upon the market. As stated elsewhere in this article, 

 the first smudge-pot devised for orchard-heating was 

 the invention of J. P. Bolton, of Fresno, California, 

 and the object of this invention was to produce a 

 device which would effect fairly complete combustion. 

 In fact, the idea in all of the more recent types of 

 orchard-heaters has been to bring about more perfect 

 combustion of the fuel-oil and a consequent reduction 

 in the amount of soot given off. Also, there has been 

 an effort to increase the burning time of the pot by 

 increasing the capacity for fuel-oil. This has been 

 partially effected by several interesting devices, but 

 the perfect pot producing complete combustion of 

 fuel-oil has yet to be invented. The so-called soot- 

 arrester of some types is a misnomer. Very extensive 

 experiments have been made with all the devices on the 

 market, and it has been shown that the plain sheet-iron 

 pot holding approximately five quarts of fuel-oil is 

 just as effective as the more complicated and expensive 

 types. This pot is inexpensive, and when made of No. 

 29 or 26 sheet-iron will cost from 5 to 8 cents. In 

 using a heater of such small size, the number to the 

 acre should not be less than 100, and preferably more 

 in districts in which periods of low temperature con- 

 tinue more than four or five hours. Owing to the 

 cheapness of such pots, a very large number may be 

 used in preference to using a few expensive heaters 

 of the reservoir type. Many small fires give better 

 results than a few large ones, as the heat is better dis- 

 tributed and convectiye air-currents are not produced. 

 It must be understood that any orchard-heating device 

 that is in any way complicated by dampers, cocks, 

 valves, and the like, must be avoided. At best, an 

 orchard-heater is roughly handled and the more expen- 

 sive and complicated types would find a very short 

 existence in actual orchard-heating practice. Further- 

 more, the matter of storage must be considered. The 

 simple pot which will nest easily and occupy very little 

 space will be more desirable. There is no objection to 

 the high-priced reservoir heater providing it is not 

 complicated, but the same results may be secured by 

 the more simple lard-pail type, holding about five 

 quarts and having a burning time of four and five 

 hours, depending upon the quality of fuel-oil used. 



Equipment for orchard-heating. The equipment 

 absolutely necessary for effective orchard-heating con- 

 sists of the following: 



1. Storage reservoir. 



2. Distributing wagon tank. 



3. Orchard-heaters. 



4. Lighters for igniting the fuel-oil. 



5. Thermometers. 



6. Frost alarm thermometers. 



(1) The storage reservoir should be built of con- 

 crete or steel and should have a capacity sufficient to 

 provide for at least five fillings of the orchard-heaters 

 that is to say, for five frost-periods. Such a reservoir, 

 if built of concrete, should be constructed in such a 

 way as to make the walls and floor one continuous 

 pouring, so as to provide against leakage of oil. Resid- 

 ual oils have no effect upon the concrete, and all leakage 



is due to improper pouring of the cement. A rich cement 

 mixture should be used. The reservoir should be so 

 placed that it may be filled and emptied by gravity. 

 At best, it is expensive to handle oil, and there should 

 be no pumping. Oil should be secured in tank-car lots, 

 and, if the proper arrangements are made, all the hand- 

 ling may be done by gravity. The reservoir should 

 have an outlet pipe 2J^ to 3 inches in diameter and 

 supplied with a close-fitting valve. A cover to keep out 

 dust and rain should also be provided. (2) The supply- 

 tank should be placed upon a heavy low truck and 

 should hold between 300 and 400 gallons. It should be 

 provided either with two heavy gate valves at the 

 rear or with two lines of hose with valves for the pur- 

 pose of distributing the oil into the orchard-heaters. 

 This tank may be the ordinary supply-tank used to 

 carry spray material. (3) The number of orchard- 

 heaters to be used to the acre will depend upon a knowl- 

 edge of the conditions under which they are to be used. 

 If the simple one-gallon type of heater is used, at least 

 100 to 120 should be provided to the acre. Besides, a 

 double row should be placed around the side from which 

 the prevailing air-movement comes in the periods of 

 frosts. In fact, it is best to reinforce all sides of the 

 orchard. After filling the heaters, they should be cov- 

 ered so as to prevent the entrance of moisture or to 

 provide against evaporation of the oil. In placing the 

 heaters, it is best to arrange them somewhere near 

 the intersections of the diagonals made by the trees; 

 but any arrangement which will not place a pot directly 

 under a tree will suffice. (4) Fuel-oil is rather difficult 

 to ignite, and a small amount of gasolene must be used 

 so as to provide for quick lighting. The best method 

 of lighting is to use a machinist's oil-can filled with 

 gasolene, and a torch made of two pieces of thin iron 

 pipe. The larger piece is fitted with a screw cap and is 

 filled with a mixture of kerosene and lard oil. A sec- 

 tion of small pipe through which is drawn a piece of 

 waste is then fitted by a reducer to the other end. The 

 waste is kept saturated with the mixture of lard and 

 kerosene and when lighted provides a very good torch. 

 This iron torch is very useful in taking off fids or caps 

 of heaters when lighting. The machinist's oil-can 

 filled with gasolene is carried in the left hand and 

 about two tablespoonfuls are poured on the surface 

 of the fuel-oil in the pots. The torch is applied and 

 the gasolene ignites, firing the heavy fuel-oil. A simpler 

 and lighter torch is easily made by wiring a piece of 

 waste into a ball and twisting the wire into a handle. 

 The waste is kept saturated by plunging it into the oil 

 of the heater, igniting it from the surface flame as it 

 is removed. (5) A most necessary part of any orchard- 

 heating equipment is a sufficient supply of fairly accu- 

 rate thermometers. There should be at least one ther- 

 mometer to the acre. The thermometers should be 

 hung with the bulb about 4 to 5 feet from the ground, 

 depending, of course, upon the relative position of the 

 fruiting area of the tree. In many orchards the ther- 

 mometers will be placed higher, in others, lower. All 

 thermometers should read correctly to within J^, and 

 if the correction be greater it should be placed upon a 

 tag attached to the thermometer. In reading the 

 thermometers, a pocket electric flashlight is much 

 better than a lantern. The heat from a lantern will 

 cause the mercury to rise before it can be read and the 

 thermometers will, therefore, not give the true atmo- 

 spheric temperature. The thermometers should be in 

 the open in order to get the approximate temperature 

 of the plants to be protected. This temperature is 

 always slightly lower than the true atmospheric 

 temperature. Besides the thermometers in the orchard, 

 other thermometers placed at a safe distance from the 

 heated area should be provided. A self-registering 

 thermometer, while not necessary as a part of the 

 equipment, would be very useful in determining the 

 actual minimum as well as the rate at which the tern- 



