154 The Spraying of Plants. 



sour. If sweet milk is used, the emulsion is not formed so 

 readily, but in other respects the two are equally valuable. If 

 the applications are not to be made immediately, it is better to 

 put the concentrated emulsion in air-tight jars until wanted, 

 otherwise fermentation will take place, and after a week or 

 more the preparation will be of little value. 



These emulsions should be diluted fifteen or twenty times 

 with water, depending upon the insect to be destroyed and the 

 foliage to be treated. 



KEROSENE AND SOAP EMULSIONS. Soap is very generally 

 preferred to milk for emulsifying kerosene and other oils. 

 Hard soap is easily obtained, and is therefore more commonly 

 used. Whale-oil soap is said to be the best for this purpose. 

 If soft soap is at hand, it may be used as well as the hard soaps, 

 since the actions of the two are practically identical. One quart 

 of soft soap is considered to be the equivalent of one-fourth pound 

 hard soap. 



Cook's Soft Soap Emulsion. "Dissolve one quart of soft 

 soap in two quarts of boiling water. Remove from the fire, 

 and, while still boiling hot, add one pint of kerosene and im- 

 mediately agitate with the pump as described above. In two 

 or three minutes the emulsion will be perfect. This should 

 be diluted by adding an equal amount of water, when it 

 is ready for use. This always emulsifies readily with hard or 

 soft water ; always remains permanent, for years even ; and is 

 very easily diluted, even in the coldest weather, and without 

 any heating. In this last respect it has no equal, so far as we 

 have experimented. The objections to it are : we cannot 

 always procure the soft soap, though many farmers make it, 

 and it is generally to be found in our markets; it occasionally 

 injures the foliage, probably owing to the caustic properties of 

 the soap. We have used this freely for years and never saw 

 any injury till the past season. In case of any such trouble we 

 may use only half the amount of soap one pint instead of one 

 quart." The emulsion should be diluted so that about one- 

 fifteenth of the liquid is kerosene, the amount varying under 

 different circumstances. 



Cook's Hard Soap Emulsion. " Dissolve one-fourth pound of 

 hard soap, Ivory, Babbitt, Jaxon, or whale-oil, etc., in two 

 quarts of water, add, as before, one pint of kerosene oil, and 



