190 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 4 



them had two-cyUnder stationary type. These machines gave much 

 better results, as we were able to maintain higher pressures, and use 

 the solid stream method in spraying woodlands, and, in many cases, 

 shade trees. 



As these machines were very heavy, they caused trouble in getting 

 around in the woodland colonies, and placing them near pond holes 

 where water was available; therefore, they did not give as good 

 satisfaction as desired. These machines, however, could be filled 

 by their own pressure from ponds, through a 2}4-'mch. suction hose, 

 and would deliver the solution at the rate of thirty-five gallons per 

 minute, thus making an advance over the previous machines, but 

 they did not do as well as expected, or give such results as were 

 needed. 



In 1909 and 1910, the State Forester's Department started experi- 

 mental work along these lines. A power outfit was placed in the field 

 last season, which proved more satisfactory than any previously 

 used. It consisted of a platform spring running gear, 400-gallon " U ''- 

 shaped tank, triplex phosphor bronze pump, and four-cylinder marine 

 type engine, capable of maintaining a steady pressure of 350 pounds. 

 By using the four-cylinder engine much less vibration resulted, and 

 the depreciation on the apparatus was greatly reduced. The pumps 

 previously used were very heavy and bulky, and not calculated to 

 maintain a pressure of over 250 pounds, so in building the new pumps, 

 which were designed by the State Forester's Department, it was 

 thought wise to use better material, and phosphor bronze was sub- 

 stituted. 



The pumps are of cylindrical design, all flat surfaces being avoided, 

 great strength and free passage of water being thus secured. The 

 weight of these pumps, when completed, was about half that of those 

 previously used. The agitators used in these outfits, up to the present 

 time, have been propeller blades attached to an agitator shaft, run- 

 ning through the lower part of the "U "-shaped tank.' These agita- 

 tors were not entirely satisfactory, and for the coming season, we shall 

 use more paddles, and feel that the settling of the lead in the bottom 

 of the tank will then be very small. On these machines, the necessary 

 pressure is determined by the length of hose which is being used in 

 the work. One-inch marline-covered hose with full way coupling 

 is used, and in lengths from 100 feet to 2,000 feet. This is determined 

 by the size of the area which we wish to spray. 



In order to' spray woodlands and shade trees effectively, it is 

 necessary to maintain 220 pounds pressure at the nozzle. We are 

 spraying several thousand acres every year, and in one woodland 

 colony, nearly 4,000 acres are being cared for, the average cost per 



