75 



consists of five to ten thousand trees, it will be found that the expense 

 per tree with this outfit is onl}^ about half of what it would be Avith 

 hand-power sprayers. 



Many dealers have placed spra34ng machines on the market in which 

 the power is derived from gasoline engines. They consist largely of 

 engines, pumps, and machinerj'^ for other uses, placed together for 

 this purpose. While a majority of these are quite well adapted to 

 the work of spraying, many improvements are possible which would 



Fig, 17 —Spraying outfit for treating tall trees (after Gould). 



increase efficiency without increasing cost. There are many makes of 

 gasoline engines, most of which are well adapted to this work. The 

 horsepower of the engines is usually too large. An outfit with which 

 the writer is most familiar is run ])y a li-horsepower gasoline engine, 

 and in ordinary spraying operations it was found that the engine was 

 too powerful, as four out of nine possible explosions were all that was 

 required to run the pumps and keep the pressure at 100 pounds. The 

 engine for sprajang purposes should bo about 1 horsepower, which 



