286 DISEASES OF TROPICAL PLANTS CH. 



READING ON HYDROMETER. 



SPRAYING APPARATUS 



For properly combating plant diseases some sort of 

 spraying apparatus is needed if satisfactory results 

 are to be obtained. There are many manufacturers of 

 spraying apparatus, and practically all manufacture 

 spraying equipment that is efficient. 



There are several types of spraying equipment 

 upon the market, and the grower has a large range 

 to choose from. Spraying machinery may be roughly 

 divided into two classes, " hand -sprayers " and 

 " power-sprayers." 



Hand-sprayers consist of some sort of a force pump 

 installed in a barrel or tank. In purchasing a spray 

 pump there are several points in the construction that 

 should be examined into. Every pump should be 

 furnished with some sort of an air-chamber in order 

 that a steady uniform pressure may be obtained. The 

 working parts of the pump that come into direct contact 

 with the spraying solution should be constructed of 

 brass or bronze, as these metals are not likely to be 

 corroded readily. 



The pump should be compact and have no pro- 

 jecting parts to catch upon limbs. It should be of 



