116 ASSOCIATION" OF ECONOMIC ENTOMOLOGISTS. 



gave the inner oil stream a tangential motion, thus forming a cone- 

 shaped spray, upon leaving the aperature, like that from a Vermorel 

 nozzle. Testing the nozzle convinced us that this section was not 

 necessary, and that it might be eliminated and the nozzle cap put 

 directly upon the ends of the two pipes. The end of the inner oil pipe 

 fits into grooves of the nozzle cap so that no connection between the 

 oil and water is possible except after they have left the nozzle. The 

 oil leaves the cap through a central, round, reamed hole, 0.02 inch in 

 diameter. Around this central orifice are two or more holes, each 

 pair being directly opposite each other and opening into the outer 

 water pipe. The holes for the water are reamed so that the streams 

 from them are directed to meet in front of the center of the nozzle 

 the same as in a calla nozzle! Here they come into contact with the 

 straight or cone-shaped oil jet and the whole breaks into a fine spray 

 evenly composed of oil and water. It is evident that if the streams 

 leave the nozzle under the same pressure and the apertures be of the 

 same diameter, the spray must then consist of 33^ per cent oil, if there 

 be two water jets and one oil jet ; 20 per cent oil, if there be four water 

 jets, etc. The percentage of oil may, therefore, be readily regulated 

 by having various nozzle caps with a different number of water 

 holes or with water holes of various sizes which have been tested to 

 give a greater percentage. 



Several such caps were made and the whole apparatus was given 

 a thorough test by us. Various minor troubles were found in its 

 structure which it would require some little time and experiment to 

 eliminate, but our tests showed that the apparatus did practically 

 what it was designed to do, and that with proper mechanical execu- 

 tion, the principles upon which it was based were undoubtedly cor- 

 rect. While its perfection was under way, the writer was called to 

 Texas, where circumstances did not permit the completion of the 

 work, and the Delaware station has. given it no further attention since 

 that time. 



It is the writer's belief that a nozzle may be perfected along this 

 line, for there is nothing specially new in the structure of the pump ; 

 and that we might thus have a perfect mixture of oil and water or 

 other mixture, which, if it could be secured, would be of the greatest 

 service against many insects. This now seems to the writer more on 

 a problem for the pump manufacturer than the entomologist, and 

 our work toward the solution of the problem is therefore made 

 public at this time. 



A brief discussion of mechanical mixing pumps followed. 

 Mr. J. B. Smith stated that good work had been done by some of 

 these pumps in certain sections in New Jersey. The general opinion 



