15 



of this kind upon the market. A majority of these are well adapted 

 to the work for which they are intended, but many valuable improve- 

 ments can yet be made which will increase the efficiency of these 

 machines with but little cost. In general, the size of engine to be 

 preferred is 1 horsepower. The cooling tanks used with the engines 

 are intended to be used when the water can not be renewed fre- 

 quently, and are about 1 foot in diameter. In spraying, the water 

 can be renewed often and the weight can be reduced considerably by 

 making these tanks of a much smaller diameter. Purchasers are 

 always given full directions in regard to the care and running of the 

 engine, so that ordinarily but little difficulty is met. The engine 

 is best placed at the rear end of the wagon frame and the pump as 

 near to it as possible. There are several types of pump which can be 

 used in this connection. Brass working parts which can be easily 



Fig. 3.— Gasoline power spraying outfit (original). 



removed are preferable-. A pressure gauge and a large air chamber 

 are necessities. For filling the tank another pump of the ' ' low-down " 

 type can be used advantageously when the water supply is to be drawn 

 from a stream or irrigating ditch. This extra pump and necessary 

 connections can be purchased for about $20, and in a season will pay 

 for itself many times over by the saving of time and labor. The gas- 

 oline engines are usually fitted up for running such a pump by means 

 of a connecting rod which can be attached to the piston of the pump. 

 While filling the tank the spray pump can be disconnected or, more 

 easily, the suction hose can be taken out of the tank. The tank may be 

 made of wood or of galvanized iron. It should be thoroughly bracJed 

 and should never be made to hold over 150 gallons. It should be 

 placed nearest the horses, because of its great weight when full of 

 the spraying solution. The best agitator is a paddle wheel, with pad- 



171 



