SPRAYING AND DUSTING APPARATUS 



71 



and constant high pressure is maintained. Unfortunately the 

 gas makes a chemical combination with lime-sulfur mixture, so 

 that this type of sprayer is not adapted for its use. A modifi- 

 cation of the gas sprayer outfit has recently been made in which 

 a gasoline engine operates an air-compressor, which places an air 

 pressure on the liquid in the tank in the same manner as would 

 the compressed carbonic-acid gas. It is claimed that these 

 outfits are superior to an ordinary gasoline engine and pump, 

 in that the liquid does not pass through the pump, and that 



FIG. 42. Carbonic-acid gas sprayer at work. 



there is therefore less wear on the pump, and that the outfit is 

 lighter. 



A somewhat similar use of compressed air is being made for 

 orchard sprayers by a few large fruit growers. The outfit 

 consists of two steel tanks holding 50 to 100 gallons each, 

 which are fitted with valves connecting them and at the outlet. 

 -One of these tanks is filled with liquid and in it is an agitator 

 operated from the wheel. The other tank is charged with com- 

 pressed air by an air-compressor stationed at the filling-station. 

 The air-pressure secured in the air-tank is sufficient to force all 



