SELECTING MACHINERY AND EQUIPMENT ^^29 



the under sides of leaves on the lower branches and for work 

 at close quarters. 



11. Control. Cut-offs to stop the flow of the material both 

 at the base of the spray rod and at the pump are advisable. 

 The former is in use continually as the operator manipulates 

 the rod and directs the spray. It enables him to save much 

 material between trees and to make minor adjustments in the 

 rod or nozzles without stopping the engine. At the pump a Y 

 connection with a cut-off attached to each prong is best. If 

 two leads of hose are employed, one may then be shut down 

 for repairs without interfering with the other. 



Cut-offs should resist corrosion, brass being the common 

 material for them. They should be simple in construction and 

 easily replaced, and the one at the base of the rod should be so 

 designed that a partial turn will shut off the flow of material. 



12. Spray Hose. Rubber spray hose for carrying the ma- 

 terial from the pump to the rod or gun should be either %, 



or % inch in diameter. The % inch size should be used 

 when the nozzles discharge more than 4 gallons per minute; 

 the %-inch hose is best for a discharge exceeding 6i/^ gallons 

 per minute. The actual inside diameters of and 

 %-inch hose are usually %6, Yiq, and %q inch, respectively, but 

 the former are trade terms. 



Hose larger than % inch is inconvenient to handle, on 

 account of its greater weight, and does not wear so well under 

 orchard conditions as that of smaller diameter. 



There is a great variation in quality of hose and no fixed 

 standard by which its quality may be determined. It is classi- 

 fied according to the number of layers of canvas used in its 

 construction, as 3-ply, etc. The quality of these plies varies 

 greatly from fine duck to cheap sheeting. The greater the 

 number of plies and the better the material used, the more du- 

 rable the hose. The best hose usually has from 5 to 9 plies. 



The length of hose required depends primarily on the dis- 

 tance between trees and also on the size of the trees, because 

 more hose is needed to w^ork about a tree with a top large in cir- 



