PRINCIPLES OF SPRAYING 



from one part of the mixture above mentioned 

 or of the commercial preparation, to from 

 seven to ten parts of water, according to the 

 density test of the material, which should be 

 around twenty-eight per cent. Beaume (a scale 

 for measuring the density of a liquid) for home 

 made, and thirty-two per cent, for the commer- 

 cial mixture. 



Any good soap is effective In destroying soft 

 bodied Insects such as plant lice. The fish oil 

 soaps, although variable In composition, are 

 often valuable, especially the one known In the 

 trade as whale oil soap. This soap dissolved 

 in water by boiling at the rate of two pounds 

 of soap to one gallon of water, makes a good 

 winter spray for scale but should be applied 

 before It gets cold as It is then apt to become 

 gelatinous. For a summer contact spray against 

 lice, one pound of soap to seven gallons of water 

 is strong enough to be effective. It Is objection- 

 able because of Its odor and because It Is dis- 

 agreeable to make and handle. Lime sulphur 

 is to be preferred as a winter spray, but the 

 soap spray Is often necessary and valuable for 

 summer sucking Insects. 



Kerosene emulsion was formerly more com- 

 monly used than now against the scale and plant 

 113 



