64 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



2. It should have a large air chamber within the barrel, and 

 not projecting above it 



3. As few of the working parts of the pump as possible should 

 be above the head of the barrel, as exposed parts are easily broken. 



4. The cylinder, plunger, valves and working parts should be of 

 brass. The handles and other parts commonly made of cast iron 

 are much more durable when made of malleable or galvanized iron. 



5. There should be a good mechanical agitator of the paddle 

 type, preferably arranged so that it can be worked with the 





FIG. 35. Two types of double-acting lever pumps, to be mounted 

 on truck and connected with tank. 



pump handle without operating the pump. An agitator is 

 essential to keeping the mixture in suspension. Agitators of the 

 so-called "jet-type," in which a stream from the bottom of the 

 cylinder is supposed to agitate the liquid, are unsatisfactory 

 and allow a loss of pressure without sufficiently agitating the 

 liquid. 



6. The pump should be so attached to the barrel that it can 

 be quickly removed for repairs. Those pumps which have lugs 

 for attaching the pump plate to the barrel are much better than 

 those with screws. 



