Kerosene Emulsions. 83 



in progress at Crescent City, Fla. 1 "Experiments with 

 NeaPs mixture gave, upon the whole, rather disappointing- 

 results." I have not learned what was the composition of this 

 mixture, but it may have been an emulsion of kerosene in soap 

 water, for Dr. Xeal did considerable work in this direction. On 

 Oct. 10, 1882, he wrote from Archer, Fla., to the chief of the 

 Division of Entomology regarding these formulas, only two of 

 which it is necessary to mention. 2 These were also applied for 

 the destruction of the cotton worm : 



"1. Four pounds whale-oil soap were dissolved in one gal- 

 lon of water with heat ; to this, kerosene was added gradually 

 till it was found that one gallon kerosene made a good emul- 

 sion, capable of being diluted to one per cent without at once 

 disintegrating. 



"2. Four pounds resin soap, common bar or yellow soap, 

 were dissolved in one gallon water. One gallon kerosene grad- 

 ually added, with constant agitation. The greater the per cent 

 of resin in the soap, the better was the emulsion I found it 

 made, which would indicate that such a soap for this purpose 

 would no doubt be a valuable article in the market." 



On Nov. 28, 1882, Hubbard wrote in detail concerning 

 the use of kerosene, and also criticised NeaPs formulas. He 

 says : 3 



" Experiments made in September with kerosene washes on 

 purple scale show that the eggs are much more difficult to kill 

 than I had supposed. They have been killed by 66 per cent 

 kerosene and soap emulsions diluted 1 to 9. ... I have care- 

 fully gone over Dr. NeaPs report and have a few comments to 

 add to my former communication. 



" Dr. Neal says ' the greater the percentage of resin in the 

 soap the better the emulsion I found it made.' This may be 

 true of the emulsion, but when diluted, the resin, or a large part 

 of it, separates from the liquid and forms a waxy scum on the 

 surface, which clogs the pump and nozzle, and is troublesome 

 unless removed. . . . The strongest emulsion used by Dr. Neal 

 contains 50 per cent of oil and the strongest wash a dilution of 

 1 to 9. My experiments with milk emulsion of this strength 

 did not in the end prove satisfactory, and I long ago decided to 



1 U. S. Dept. ofAgric. Div. of Ent. 1883, Bull. 1, 10. 



2 Hid. 32. s Ibid. IT, 18. 



