190 OHIO EXPERIMENT STATION: BULLETIN 332 



large capacity of the machine, contributes greatly toward facili- 

 tating the work and reducing its cost. (See Plates IX, X, XI, XII 

 and XIII.) In spraying with the solid-stream type, it is much 

 easier to operate against adverse wind currents both with regard to 

 placing the spraying material where desired and in preventing its 

 soiling nearby buildings. Those who have had experience in city 

 spraying will recall the inconvenience caused by the variable winds 

 of the streets. (See Plate X, Fig. 1.) 



The solid-stream sprayers are of course of comparatively recent 

 development, and thus have not approached the point of standard- 

 ization reached by the mist types ; hence it is impossible to set forth 

 in such complete detail the specifications of a solid-stream spraying 

 outfit as has been done with the mist machine. Such an attempt 

 would merely result in giving the specifications of each of the 

 several machines on the market which claim the right to the title 

 of solid-stream sprayers. 



In general, however, the solid-stream machines are heavier and 

 stronger in every way. The engine is rarely less than 10 horse- 

 power ; the pump of the multiple cylinder type ; the tank of 400 or 

 500 gallons capacity ; the truck stronger and more durable ; and the 

 hose larger in diameter. 



The increased strength and size are made necessary because 

 of the increased capacity and pressures required in this kind of 

 work. In addition the workmanship must be of the highest quality. 

 When a machine is operated under 350 to 400 pounds pressure at 

 the pump in order to insure 250 pounds pressure by the time the 

 spraying material reaches the nozzle, every item of its makeup 

 must be well-nigh perfect in both workmanship and repair. 



The general increase in size and capacity of the machine as 

 might be expected is found to extend to the hose, since the usual 

 sizes are 1^2, inch, I14 inch and 1 inch. Unusual lengths are fre- 

 quently employed, sometimes as much as 2,000 feet in a single line. 

 Only hose of the highest quality will withstand the high pressures, 

 and the ordinary couplings are useless. A specially constructed 

 clamp coupling is required. 



The spraying rod and nozzle are decidedly different from those 

 used on mist sprayers. Rarely is a rod more than 6 or 8 feet long 

 employed, and it is heavier and more rigid than the ordinary bamboo 

 extension rod. The nozzle, as has been stated previously, is a 

 straight bronze tube having a smooth aperture varying from one- 

 eighth inch to five-sixteenth inch in diameter. (Such a spraying 

 rod and nozzle are shown in Plate XIV, Fig. 1.) 



