THE SAN JOSE SCALE AND ITS CONTROL. 25 
sene will combine readily with the naphtha soap in water when thor- 
oughly agitated. Of naphtha soap, however, double the quantity 
given in the foregoing formula will be required, and soft or rain water 
should be used in making the emulsion. In regions where the water 
is “hard” this should first be broken with a little caustic potash or 
soda, such as common lye, before use for dilution, to prevent the 
soap from combining with the lime or magnesia present, thus liberat- 
ing some of the kerosene; or rain water may be employed. 
CrupDE PETROLEUM EMULSION. 
Crude petroleum emulsion may be prepared in identically the 
same way as described for kerosene emulsion, substituting crude 
petroleum for kerosene. The same dilutions for winter and summer 
Fig. 15.—Knapsack sprayer suitable for spraying Fic. 16.—Barrel sprayer suitable for orchard or sim- 
low-growing plants. (Author’s illustration.) ilar large-scale work. (Author’sillustration.) 
spraying should be made as prescribed for kerosene emulsion, but it 
should be noted that for summer treatments of trees in foliage the 
kerosene emulsion is preferable, as it is less likely to cause injury. 
MiscisLE Ons. 
‘ 
Under the heading ‘miscible oils” are to be designated several 
proprietary preparations which are essentially petroleum oils with the 
addition of a vegetable oil and an alkali, to secure ready saponifica- 
tion with water. These come in concentrated solutions and the 
spray is prepared by adding a specified amount of water. In point 
of convenience they leave little to be desired. Miscible oils have 
come into use in place of kerosene or crude petroleum, either pure or 
in emulsions, and have a distinct usefulness as winter sprays about 
the same as have the concentrated lime-sulphur solutions. As has 
