Mechanical Appliances 583: 



can be covered in a day, and the benefits 

 derived from thus cleansing the trees and ex- 

 terminating pests are such as to give a return of 

 many times the first cost of the machine even 

 in one season. 



The same firm also make a very useful Knap- 

 sack sprayer which is specially constructed for 

 dealing with all kinds of chemical washes. It 

 has outside pumps and all its working parts are 

 of gunmetal, so that there is nothing to get out 

 of order, or become wasted away by the action 

 of the chemical washes used. 



They also make power-driven spraying plants, 

 which are almost indispensable for large plan- 

 tations. The engine may be either oil or petrol, 

 as shown in the illustrations on pp. 579 and 

 582. The pumps are of varying capacities, 

 dealing with from 700 to 2,000 gallons per 

 hour ; it will be noted that a stirring arrange- 

 ment is provided so as to keep the wash 

 thoroughly mixed. 



The lighter types of these plants are usually 

 provided with hose of a good length and are 

 drawn about in the plantation and the wash 

 conveyed to them in water-barrels. The heavier 

 types are usually kept on the outside of the 

 plantation and a system of piping used in con- 

 nection with them to convey the wash to the 

 required place as illustrated on p. 584. (The 

 same apparatus can also be used to apply water 

 to the plants.) The main consists of a series of 

 light galvanized steel pipes having screwed ends 



