Spraying Devices and Machinery. 189 



several minor changes have been made. His pump (Fig. 9) 

 consists of a knapsack tank carried on the back of the 

 operator. The pump proper is composed of a tube or cylin- 

 der which projects a short distance above the top of the tank, 

 the lower end being near the bottom of the reservoir. The 

 piston is moved by means of a handle which extends forward 

 in such a manner that it can be worked easily by the person 

 carrying the pump. No pressure is brought to bear upon the air 

 above the liquid, but all necessary force is applied directly to 

 the liquid by means of the 

 working parts of the pump. 

 The Galloway knapsack 

 sprayer, as the machine is 

 commonly called, was first 

 manufactured by two firms 

 in Washington, D.C. 1 A few 

 other manufacturers almost 

 immediately began the con- 

 struction of this class of 

 pumps, but on account of 

 the limited demand, they 

 were not produced in nearly 

 such large quantities as were 

 the various hand and barrel 

 pumps. One company 2 put 

 an enormous air chamber 

 above the tank the first year 

 it sold the machine ; as this 

 feature was advertised only 

 one year it is good evidence that its use was not advisable. 

 Later styles of these pumps have varied in the shape of the 

 tank, and many desirable features have been added, but the gen- 

 eral plan has remained unchanged. They are almost without 

 exception made of copper and brass, and consequently withstand 

 the corroding action wrought by many of the materials applied. 

 Rumsey & Co. has departed from the Galloway sprayer, and 

 now manufactures a pump in which air is forced into the tank 

 by means of a pump, and this air pressure forces out the liquid. 



FIG. 9. The "Galloway" knapsack pump. 



i Albinson & Co.; Leitch & Sons. 



* Field Force Pump Co., Lockport, N.Y. 



