IXSECTICIDES, PREVENTIVES, AND MACHINERY. 459 



ten to fifteen feet. This nozzle has proved very satisfactory in 

 orchard work, but has the disadvantage of clogging very much 

 more readily than the cyclone, and of not clearing easily when 

 it does clog. With a proper netting at the end of the suction 

 pipe, the tendency to clog can be reduced to a minimum, and 

 with a Httle practice in actual field work, the nozzle has proved 

 satisfactory . 



The McGowen nozzle is of yet a different type, and throws a 

 fan-shaped spray the quantity of which can 

 be varied by adjusting a spring which regu- 

 lates the size of the opening. The nozzle 

 has the advantage of being self-clearing, — 

 that is to say, any obstruction which may 

 lodge at the opening creates a pressure 

 sufficient to overcome the strength of the 

 spring, and the vent broadens sufficiently 

 to allow the escape of anything that can 

 get into the barrel of the nozzle. As soon 

 as the obstruction is removed, the spring 

 restores the opening as originally set. The 

 peculiarities of this nozzle are that the spray 

 can be thrown a much greater distance than 

 with any of the types previously mentioned, 

 and that the amount of liquid to be dis- 

 charged can be regulated. It has certain 

 advantages, therefore, in an orchard where 

 large trees are to be treated, but it does 

 not throw as fine a spray over so great a 

 surface as the Vermorel. 



For spraying very large trees many 

 growers have found a cheap graduating 

 nozzle effective. This is a cylinder with 

 a large flared opening, through which a 

 conical pin may be forced, even to its com- 

 plete closure. When the pin is completely The AicGowen nozzle 

 retracted, which is done by turning the ^ ^^^^^i"" through its 



. . tip to show working- parts. 



barrel of the nozzle, a solid jet is thrown, 



and any intermediate grade between this and a tolerably fine 

 spray may be readily obtained. For spraying shade-trees nothing 



