METHODS NOW USED IN FIGHTING THE GIPSY MOTH. 67 



When a machine of this type (PL X) is used and a pressure held 

 at from 200 to 250 pounds, trees from 60 to 75 feet high can be thor- 

 oughly sprayed from the ground. It is necessary in spraying the 

 woodland areas to use long lines of hose, and this requires the use of 

 a considerable number of men to move the hose about rapidly, so 

 that the spray material can be well distributed by the man holding 

 the nozzle. In the work along roadsides this system was used in 

 1907 with satisfactory results, but the time required for moving the 

 hose greatly increased the cost of treatment. In order to diminish 

 the cost of applying poison to the roadside areas, and also to enable 

 the workmen to treat a greater mileage in a given length of time, a 

 special arrangement was devised by Mr. Rogers which is known as a 

 'Svater tower." This is set up on top of the tank and is mounted on 

 a mast 6^ feet high made of 2^-inch piping which is provided with 

 braces to hold it in perpendicular position. It is attached to the top 

 of the tank with bolts so that it can be laid down when not in use. 

 At the top of the mast is a threaded street L made on free to the mast 

 and a T is made onto the L in such a manner as to provide what is 

 practically a universal joint. Through the T a length of l|-inch, 

 16-gauge steel tubing is placed, which is fitted with collars to hold it 

 firmly in position. The tube is about 20 feet long; at the outer end 

 the nozzle is attached, while to the other, which extends only 

 about 4 feet from the point of attachment to the mast, is coupled the 

 hose carrying the solution. 



The tube near the end where the hose enters is reenforce'd by a 

 quantity of lead which makes it nearly balanced on the mast. The 

 nozzle is raised by lowering the reenforced end of the tube, and when 

 the sprayer is in operation the nozzle is about 25 feet from the ground. 

 With this arrangement, if the pressure is maintained at 200 pounds 

 and a J-inch nozzle used, trees 80 to 90 feet in height can be readily 

 sprayed. If the wind is light or favorable, a strip along one side of 

 the road 100 feet deep, or more, can be treated. It is impossible to 

 use this arrangement with satisfactory results if the wind is blowing 

 from the strip, but under favorable conditions good work can be 

 done if the sprayer moves along the road while the machine is in 

 operation. (See PI. XL) It is more effective to spray these strips 

 twice, as this assures better distribution of the poison. A modifica- 

 tion of this system was tried during the past summer and consisted 

 simply of using the tower for elevating the spray and treating the 

 high trees and growth as far back as possible from the roadway, while 

 at the same time another hand nozzle, with smaller tip of the same 

 type as the one on the tower, was operated by a man standing on the 

 top of the tank. The latter nozzle was used for treating the trees 

 close to the road, and by this modification more thorough work was 

 done. (See fig. 18.) 



