63 



was the tii\st to suggt'.st and aiiuouiice this remedy, I was the tirst to 

 prove and aunouuce positively that it is both safe and effective. So far 

 as I know I was also the first to determine the best proportion — 1 pound 

 to 200 gallons of water— and to show that it is safe to pasture in an or- 

 chard at once after the poison is applied if the application is properly 

 made. 



Mr. Osborn read the following paper : 



AN EXPERIMENT WITH KEROSENE EMULSIONS. 



By Herbert Osborn, Ames, Iowa. 



The most satisfiictory method of preparing the valuable kerosene 

 emulsion is desired by all and a comparative test made this season may 

 be of interest. 



The tirst was a preparation in which the formula advocated by Pro- 

 fessor Cook was carefully followed, using the hard soap and not the 

 soft soap formula, the materials while still hot being thoroughly mixed 

 with an egg beater. 



The result was that we had what appeared to be an excellent emul- 

 sion, but in a glass jar we could soon see a separation taking place, the 

 white emulsified pan rising to the top and the water or soapsuds 

 gradually increasing at the bottom. This continued until there was 

 about two-thirds or a little more of soapsuds and one-third or less of 

 emulsion above it. 



While this at first could be readily mixed again a day later, the soap- 

 suds in the bottom had hardened into a jelly that when mixed with 

 additional water would but incompletely dissolve and the clots included 

 caused great inconvenience by clogging the nozzle. 



The other preparation made according to the usual formula for soap 

 emulsion (the Eiley-Hubbard formula) emulsified and remained fixed 

 with but a very few drops of soapsuds gathering at the bottom, even 

 after days of standing, showing that the proportions were such that 

 the soap water and kerosene balanced each other. This thickened to a 

 buttery consistence, but dissolved perfectly in water, and only a trace 

 of oil arose to the surface when thus mixed. 



A microscopical examination of the substance prepared by Professor' 

 Cook's formula showed the buttery mass above to be apparently a good 

 emulsion and the jelly-like mass below to contain scarcely any traces of 

 oil globules. A similar examination of the second preparation showed 

 in different samples as usual a uniform emulsion. 



I conclude that in the first case I formed an emulsion, that is the oil 

 was broken into minute globules and these coated with a film of soap- 

 suds so that they did not coalesce, but that there was such an excess of 

 soapsuds that the emulsion separated therefrom and rose to the top. 



It is evident, I think, at sight that the preferable preparation is the 



