30 



Mr. Howard remarked that a stream of water produced by a pressure 

 of 75 pounds to the square inch, mentioned by Mr. Aldricli as obtained 

 from his hydrants, was quite sufficient to kill insects, with the excep- 

 tion of scales, without the addition of oil. 



Mr. Lintner asked if the oil and water mixture referred to in the 

 various apparatus described in the papers could be properly considered 

 an emulsion. 



Mr. Marlatt said that an oil emulsion was merely the breakiug up 

 of the oil into minute globules in the emulsifying agent, and that on 

 this basis the water and oil mixture, as long as permanent, was as 

 properly an emulsion as the kerosene and milk mixture. He referred 

 also to the fact that emulsions are often made with solid ingredients, 

 as powdered lime. 



Mr. Southwick referred to a nozzle which had lately come under his 

 observation, which effects the mixture of the insecticide element with 

 water at the moment of sprayiug. He had not yet experimented with it. 



Mr. Marlatt said that from the description Mr. Southwick undoubt- 

 edly had in mind theGillmore nozzle (to which Mr. Southwick assented), 

 and said that Mr. Gillmore had been at the Department, and some very 

 careful tests were made with this nozzle with various insecticide agents. 

 The character of the nozzle and the practical objections to its use as at 

 present constructed were pointed out. 



Mr. Forbush said he knew of a similar principle at one time employed 

 by a fire apparatus company to mix a tire extingnisher with water at 

 the moment of spraying. 



Mr. Smith said it was very encouraging to see such decided interest 

 taken in the manufacture and improvement of machinery for the appli- 

 cation of insecticide mixtures. He was of the opinion that the origina- 

 tion of new devices and the work of perfecting old ones or overcjoming 

 mechanical difticulties may be safely left to manufacturers, whom he 

 had always found very ready to adopt suggestions in the matter of 

 the betterment of apparatus. In this connection he referred also to the 

 adoption by the Climax Pump Company of an improvement in the kero- 

 sene knapsack sprayer suggested by Mr. Goff'. His experience with the 

 improved knapsack sprayer, he said, corresponded very closely with 

 that detailed by Mr. Marlatt. 



Mr. Marlatt, referring again to the device suggested by Mr. C. M. 

 Weed, pointed out that while the arrangement of the kerosene and oil 

 reservoirs suggested by this author would probably obviate several of 

 the difficulties, still an important objection, arising from the oil escap- 

 ing into the water chamber during the action of the pump or immediately 

 thereafter, was not corrected by this means, although possibly rectified 

 by the combination suggested by Mr. Gotf in a communication in Garden 

 and Foxcst of April 10, 1895 (vol. viii, p. 143). 



