SPRAYING AND DUSTING APPARATUS 



63 



is compressed by an air-pump, and spraying continues until 



the pressure runs down, when 



a stopcock is turned and the 



pressure is again raised by pump- 



ing. The tank holds from 



3 to 5 gallons, and is carried 



beneath one arm, slung by a 



strap over the other shoulder. 



The chief objections to this type 



are that it is not very con- 



venient to fill, though the newer 



models are much improved, is 



not readily repaired, has no 



agitator, and requires frequent 



pumping. On the other hand, 



they are easily carried, ' do not 



leak, and leave both hands free, 



so that one might be used for 



spraying a small tree from a step- 



ladder. These compressed-air sprayers cost from $5 to $8. 



Barrel Pumps. 

 The most serviceable 

 spray pump for the 

 average farm is the 

 barrel pump. With a 

 good barrel pump 100 

 to 150 full-grown 

 apple trees may be 

 sprayed in a day, so 

 that it will be found 

 sufficient for an or- 

 chard of 500 trees or 

 less. By using a row- 

 spraying attachment, 

 a few acres of pota- 



Fl .- -~ of the best types of 

 knapsack sprayers. Note foot- 

 rest, agitator, handle, and wide 



straps> ( Demin g Co -) 



FIG. 31.-The knapsack sprayer in use. 

 (Spramotor Co.) 



