REPORT OF THE ENTOMOLOGIST. 



331 



tion. It cannot be too strongly impressed upon all who nse kerosene 

 as an insecticide, that it can be considered a safe remedy only when 

 properly emulsified. The formula for the kerosene and soap emulsion, 

 astound most satisfactory by Mr. Hubbard, is as follows: 



Kerosene 2 galIons=G7 per cent. 



Common soap or whale-oil soap i pound { «« naT . 



Water 1 gallon \ — M P er cent ' 



Heat the solution of soap and add it boiling hot to the kerosene. Churn the mix- 

 ture by means of a force pump and spray-nozzle for five or ten minutes. The emul- 

 sion, if perfect, forms a cream, which thickens on cooling, and should adhere without 

 oilinessto the surface of glass. Dilute, before using, one part of the emulsion with 

 nine parts of cold w ater. The above formula gives three gallons of emulsion, and 

 makes, when diluted, thirty gallons of wash. 



The kerosene and soap mixture, especially when the latter is warmed, 

 forms upon very moderate agitation, an apparent union j but the mix- 

 ture is not stable, and separates on standing or when cooled or diluted 

 by the addition of water. A proper emulsion of kerosene is obtained 

 only upon violent agitation. It is formed, not gradually, but suddenly: 

 in short, to use a familiar phrase, "it comes" like butter. The time re- 

 quired in churning depends somewhat upon the violence of the agita- 

 tion, but still more upon the temperature, which, however, need not be 

 much above blood heat. 



When obtained, an emulsion of kerosene and soap is known by the 

 perfect union of the iugredients, and the absence of oiliuess, so that 

 the liquid clings to the surface of glass or metal. It resembles a rich 

 cream, more or less thickened according to the proportion of soap used 

 in the mixture. 



These details have been fully set forth in previous reports, but it 

 seems necessary to again refer to them, because, while the value of the 

 kerosene emulsions as insecticides has been widely acknowledged, the 

 important point of thorough emulsification has not been sufficiently 

 recognized, and the agricultural press of the country in the discussion 

 of this new application of an old remedy have very generally omitted 

 to mention the methods by which a perfect emulsion may be secured. 



Thus in a horticultural journal of wide distribution we find the fol- 

 lowing: "Mr. E. L. Sturtevant, director of the experimental farm at 

 Geneva, N. Y., says that an emulsion, composed of one ounce of common 

 soap, one pint of kerosene oil, and one and one-half gallons of water, 

 kept continually stirred while using to prevent the oil floating on the sur- 

 face, and used through the rose of a water-pot, will destroy all worms 

 (on cabbage) that get thoroughly wet with the mixture," &c. The 

 italics, which are our own, sufficiently indicate the unstable nature of 

 the mixture, to which this writer wrongly gives the name emulsion. • 



An officer of another State institution, having become a discoverer 

 of the means of diluting kerosene by emulsification with milk, shortly 

 after our publication of this method, repeatedly recommended a mixture 

 of kerosene made by stirring simply, admitting, however, that fc< if to 

 be used very extensively, the permanent emulsion might be more con- 

 venient." 



In Florida, where the original directions for making a good emulsion 

 have been widely distributed, and where the remedy itself is rapidly 

 coining into universal use among truck farmers, as w r ell as orange and 

 fruit growers, there is still need of greater care than is generally given 

 to the preparation of the wash. 



Failure in forming a stable emulsion is due in most cases to insuffi- 

 cient agitation of the mixture. The emulsion can be very quickly and 

 easily made by using a good force pump, so constructed that it can be 



