SMALL HAND PUMPS 93 
Knapsack Pumps 
Knapsack pumps consist of an oblong tank furnished with straps 
for hanging on the back, and provided with a small, inclosed 
pump, the handle of which projects forward over one’s shoulder. 
They are not in general favor. The apparatus is fairly heavy 
to carry, and is likely to 
spill liquid down one’s back. 
Fie. 58.— A knapsack sprayer. Fic. 59.— An automatic sprayer. 
Original. Original. 
Automatic Sprayers 
Automatic sprayers are air-tight evlinders designed to be carried by 
hand. The cylinder is filled partly full of the spray material, the top 
fastened on, and by means of a self-contained pump air is forced in 
until the liquid within is under pressure. A valve allows the spray to 
be driven out through the nozzle as desired. The apparatus is handy, 
and desirable for garden work. Its principal disadvantage is the lack of 
an agitator. Only the brass spravers should be purchased. Those in 
which the tank is made of iron, while cheaper, will not give satisfaction. 
A light extension rod may be attached to the cylinder, and the 
apparatus used for spraying small trees, if only a few are to be 
treated. 
