Emulsions 79 



n. MISCIBLE OILS 



There are preparations on the market 

 which contain various oils with the emulsify- 

 ing agent already added. These are ready 

 to use after the addition of water. 



Procedure. — Making sure that all the 

 apparatus used is clean, get 10 cc. of a 

 miscible oil and dilute it with 12 volums of 

 water. If free oil appears on the surface 

 after standing a minute clean the apparatus 

 once more and repeat the experiment. 



NOTES 



Kerosene emulsion is an old remedy for in- 

 sects that do not chew and consequently can- 

 not be poisond. Such sucking insects have 

 to be attackt thru their breathing apparatus. 

 The aphis is an example. Kerosene alone will 

 burn foUage badly. The emulsion allows the 

 use of so httle kerosene that no harm is done 

 the foliage, there still being sufficient to de- 

 stroy the insect. In pract se the happy 

 medium is sometimes hard to reach. Kero- 

 sene emulsion is practically replaced by solu- 

 tions of nicotine sulfate which are obtaind 

 from refuse tobacco. 



The miscible oils are a standard remedy for 

 scale insects and are applied in the winter or 

 spring before the buds start. It is more 



