February, '19] britton and zappe: kerosene v. nicotine 73 



Though the materials for the nicotine solution cost fully twice as 

 much as for the kerosene emulsion, it required a little less work in 

 preparation. The materials for kerosene emulsion could be obtained 

 from any grocer in city or country, but nicotine solution was difficult 

 to obtain promptly, and had become scarce in Connecticut on account 

 of the unusual demand for it. 



Mr. T. H. Parks: I would like to ask Dr. Britton if he had any 

 visible burning or ill effects from combining nicotine sulphate with 

 arsenate of lead and soap. 



Mr. W. E. Britton: We didn't dare try it on a large field. We 

 tried it on a few rows and saw some injury, though very slight. Of 

 course the field had been sprayed previously with arsenate of lead, 

 even where we used the nicotine solution and soap to kill aphids only. 



Mr. J. S. Houser: We had one group of growers in eastern Ohio, 

 who thought that the melting of the soap was too much bother, and 

 they used washing powder, in combination with the nicotine sulphate 

 and got results comparable to those obtained from the use of nicotine 

 sulphate and laundry soap chipped and dissolved. I would like to 

 ask if any of the entomologists here had experience of that kind; it 

 facilitates the operation wonderfully because you don't have to bother 

 with the fire and dissohdng your soap if you use common washing 

 powder. 



Mr. W. a. Riley: It seems to me that in the work of Mr. Moore, 

 Mr. Graham and Mr. Marcovitch, which was interrupted by the war, 

 but the preliminary results of which were published in the Journal of 

 Agricultvral Research, they show that you might as well use the powder 

 as soap. In other words the washing powder just as the soaps and 

 various kerosenes used are likely to give good results, but the essential 

 parts of their work was to show that the variation in kerosenes on the 

 market was so astonishing that the variations and results obtainable 

 from the sprays from the kerosene emulsions could be accounted for in 

 many cases by these variations in the composition of the kerosenes 

 that were available on the market, and likewise that the soaps differed 

 enough to give astonishingly different results, depending upon the 

 soap that was used. 



For an illustration, in one of the common formulae published, there is 

 the recommendation of using ivory soap. Without knowing the 

 details of Mr. Moore's work sufficiently to point it out, he found that 

 this was not only useless, but nullified the effect of the particular spray 

 that it was rcconmiended in. And so it is perfectly clear from his 

 results that in order to know what to recommend in the way of these 



