Proceedings^ 1915. 15 



experiuiental and iiracHcal use in California. Tliey are vei'.v closely allied to the 

 common insecticide, " whale-oil soap and (luassia-chiiis," and the more recent 

 " kerosene emulsion." 



The orehardist can obtain commercial oil ennilsions and miscible oils of different 

 [lenetrating strengths, just as he can buy commercial lime-sulphur of guaranteed 

 strength, but, as in the case of comparative costs of commercial and home-made 

 lime-sulphur, the commercial Is a great deal more expensive. Even though this is 

 an important economic fact, the average orehardist would do better !iy buying the 

 prepared oil sprays than by attempting to make anything but the simiilest oil 

 ennilsions on the ranch. 



There are many factors hard to overcome in the home manufacture of oil 

 emulsions. The ideal emulsion is undoubtedly one made from miscible oils, which 

 are those made by mixing mineral oils of paraffin base with vegetable and some 

 creosote oils, and are not oils in their natural crude state. In simple words, a 

 miscible oil, or one which mixes uniformly in water and is therefore capable of 

 dilution for spraying, is an oil for which a proper soap has been found for the 

 purpose of emulsifying. Thus in British Columbia we can buy many different tyiies, 

 such as crude oil. topped crude oil, fuel and stove distillates, and kerosene, all 

 of which need a different soap for iiroijer emulsion. 



Not only does each type of oil require different soaps, but the penetrating power 

 varies greatly with the gravity strength of the oil, and therefore the amount of 

 dilution necessary to iirevent injury is hard to ascertain. Oil" companies sell their 

 products under certain tests indicated in degrees Baume. It must be noted that the 

 higher the figure in degrees Baume, the lighter the oil. In measuring densities of 

 liquids lighter than water, the Baume scale begins at 10, which is the density of 

 water. For measuring liquids heavier than water, the density on the Baume scale 

 is placed at zero. Consequently the Baume scale is an almost obsolete measure of 

 density, and in order to get the exact density of any liquid, conversion tables are 

 necessary if the Beaume hydrometer is used. 



The different prepared emulsions put on the market are carefully made from 

 oils of a definite gravity test in an emuLsion carrying about the following propor- 

 tions: So per cent, hydrocarbon oils (paraffin series), 4 i)er cent, phenols (mostl.v 

 cresylie acid), and about 11 per cent, inert matter. These have proven to be very 

 satisfactory in commercial use when diluted so that 20 and 16 gallons respectively 

 make 200 gallons of spray, and seem to carry nearly correct physical characteristics 

 to give proi)er penetration without injury to trees. 



Both the crude and distillate oil emulsions contain the same ingredients as 

 given above, the advantage of the distillate over the crude being mainly that for 

 spring aud summer use it dilutes more uniformly and can be sprayed on the trees 

 with less danger of injury. The crude-oil emulsion is used chiefly as a dormant 

 insecticide. 



Now, in home manufacture, the orehardist can but follow certain cautious 

 principles gleaned from the experience of those engaged in scientific manufacture, 

 and so make the best of oils obtainable, such as kerosene, gas, lubricating, stove, 

 and sloii distillates, and crude oil. He will have to emulsify them by using ordinary 

 whale-oil soap (olin acid) with common lye. Kmulsions made from crude oil or slop 

 distillates, in the writer's opinion, should be used only as dormant insecticide spra.vs. 

 As such they are effective and fairly safe. Tested by Baume scale, they will run 

 from 13 to 19 degrees, with a specific gravity of 0.9800 in crude oil to 0.9400 in the 

 slop distillates. This, you will note, is not as good an oil as the commercial concerns 

 put into their crude-oil emulsion, which is generally a natural crude oil, testing 23° 

 Baume, and is not commonly obtainable in British Columbia. However, for purely 

 winter use, a safe insecticide can be made from a 19-degree slop distillate by the 

 following formula used successfully by Oregon State Experimental Station : Fish-oil 

 or whale-oil soap, 5 lb.; lye, 1 lb.; crude oil. slop distillate, gallons; water, 43 

 gabous; makiug a total of 50 gallons. 



