15G REPORT 4, UNITED STATES EKTOMOLOGICAL COMMISSION. 



Agriculture: -'The requisite amouut of kerosene and water is placed in 

 a barrel or pail, and with the syringe a syringeful several times squirted 

 into the barrel, when the mixture must be quickly applied before the 

 oil and water separate." When converted into soap by means of lye and 

 boiling, kerosene, like any^ other oil, can easily be diluted with water to 

 any extent, but loses in this form much of its deadly quality ; hence its 

 application in soap form has but little effect on the Cotton Worm, though 

 it is more useful for many other insects more readily affected by sapo- 

 naceous compounds. 



When mixed with a sufficiently large quantity of wood ashes, kero- 

 sene can be applied to the leaves without damaging them, but the mix- 

 ture cannot be sprinkled in particles small enough to have much effect 

 on the worii;s. A patent was obtained by Mr. George W. Powell, of 

 Halifax County, Virginia, in April, 1876, for the simi)le mixture of one- 

 half pint of kerosene to one quart of fine, dry, well-sifted wood ashes. 

 The patentee claims that by sprinkling or scattering this preparation 

 lightly over the plants it will drive off or destroy insects of every kind 

 without injury to the leaves. 



An attempt has been made to apply the oil in form of vapor by means 

 of steam. There is no question but that the worms are killed by this ap- 

 plication, and, perhaps, without injury to the plant; but the machine 

 necessary for the production of the vapor, which will be described fur- 

 ther on, is so ponderous and awkward as to be of no practical value. 



The above-mentioned methods of applying kerosene are of little or no 

 value in our warfare against the Cotton- Worm but an important step to- 

 ward ai)ractical solution of this difficult question was made in the summer 

 of 1880. Professor Barnard, while in the field at Selma, Ala., suggested 

 the use of milk as a medium to facilitate the mixing of kerosene and 

 water. First it was found that the oil mixes much more readily with 

 the milk than with water. If a small quantity of the oil is stirred up 

 in a much larger quantity of milk, the oil particles will remain much 

 longer suspended in the milk than in water, thus permitting a practical 

 application of the mixture. It was further found that even a large pro- 

 I)ortion of the kerosene could be mixed with milk by violently shaking 

 up the closed vessel containing the mixture. Thus one part of kerosene 

 to two parts of milk would unite after several minutes' shaking to form a 

 kind of emulsion, in which the two ingredients did not separate until 

 after many hours, and which then could always be restored, by shaking, 

 to its apparently homogeneous condition. Though, in the light of subse- 

 quent discoveries, this emulsion proved to be a very imperfect one, and, in 

 fact, no emulsion at all, but only a more or less finely divided mixture of 

 the oil and milk, still it was found most useful for experimentation on a 

 small scale and vastly sux^erior to any of the old methods of applying 

 kerosene. There was no difficulty experienced in experiments on a small 

 scale in diluting this emulsion of one part of kerosene with three parts 

 of milk with any desired quantity of water. A portion of the oil sep- 



