198 JOURNAL OF ECONOMIC ENTOMOLOGY [\ol. 4 



the agitator to the engine, the paddles may be run at a rapid rate of 

 speed and the spray material kept in a violent state of agitation. 

 Where home-made lime and sulphur or other materials carrying solid 

 matter are used this form of power pump is superior to any other. 



Compressed Air Pumps 



This class of pump is of two kinds, i. e., those that are air charged 

 at a fixed station, and those that compress the air into a cylinder by 

 means of an apparatus connected with the rear wheels of the spray 

 wagon. Both of these types are worthy of recommendation under 

 certain conditions. Where no part of the spray solution will settle out, 

 as when miscible oils, prepared lime and sulphur, etc., are used, and 

 no agitation thereof is necessary, pumps that are air charged at the 

 renewal station are highly efficient. Pumps that depend on the auto- 

 matic compression of the air from the turning of the wagon wheels 

 are efficient when the trees are small and can be rapidly sprayed. 

 They are failures among large trees that require some minutes to spray 

 before any advance is made. Neither of these types has adequate 

 agitation equipment and other means must be employed wherever 

 necessary to keep the material well mixed. . 



Carbonic Acid Gas Pumps 



The working principle of carbonic acid gas pumps is almost identi- 

 cally like the compressed air type, except that the cylinder is charged 

 with carbonic acid gas instead of air. It is an efficient, serviceable 

 pump, but with respect to the agitator it is equally as inefficient as 

 the compressed air pumps. 



Spraying Accessories 



No pump, y\D matter how capable, will give service without the 

 complementary support of good spraying auxiharies of the best quality 

 and design. As much attention should be given to these as to the 

 pump itself. These accessories consist of hose, extension rod, stop 

 cocks and nozzles. 



Hose 



Nothing need be said of this save that it should be of the best quality 

 and ample length. As a matter ,of economy, it is cheaper to buy the 

 best grade of four-ply goods. This will easily last a full season or 

 longer with proper care. Cheaper grades are quick to leak and are 

 generally unsatisfactory. The better grades of hose cannot be bought 

 for less than fifteen cents per foot. 



