REMEDIES AGAINST SCALE-INSECTS. 



93 



of keroseue. The mixture requires to be very violently churned for a 

 period, varying with the temperature, from five or ten minutes to half 

 an hour. If the mixture is quite hot the emulsion is very easily and 

 quickly formed. It is quite thin while warm, but thickens on cooling. 

 If cold, the process is delayed, but after continued agitation the emul- 

 sion forms suddenly, as in butter making, and becomes at once an ivory- 

 white glistening paste, or jelly. 



To form a perfectly stable emulsion more violent agitation is re- 

 quired than can be effected by hand stirring, or by dashing in an ordi- 

 nary churn. The particles of oil and milk are more readily driven 

 into union by passing the mixture through the spray-nozzle of a force- 

 pump. 



The aquapult pump (Fig. 43), which is also one of the most effective in- 

 struments for spraying trees, may 

 be satisfactorily used for this pur- 

 pose. The pump is inserted in a 

 pail or tub containing the mix- 

 ture, and this is pumped back 

 into the same receptacle through 

 the flexible hose and spray-nozzle 

 until the emulsion is formed. 

 From 3 to 5 gallons of emulsion 

 may be churned at one time by 

 means of the ordinary hand form 

 of this pump. For larger quan- 

 tities a larger pump or some form 

 of druggist's churn will be re- 

 quired. 



The emulsion, if well made, is 

 permanent, provided it is not ex- 

 posed to the air, which causes in 

 time a partial separation of the 

 oil. The union of the ingredi- 

 ents is purely mechanical, and 



FIG. 43. The aquapult. 



the presence of the kerosene does 

 not prevent the fermentation of 

 the milk, which will become sour and curdle without, however, separat- 

 ing from the oil. 



For fresh milk may be substituted an equivalent of condensed milk 

 and water, or of sour milk. If sour milk is used no subsequent curd- 

 ling of the emulsion takes place, and it is therefore preferable to sweet 

 milk. 



The milk emulsions may be diluted in water to any extent, and if 

 cold require to be thinned at first with a small quantity of water. 

 One part of emulsion to nine or ten parts of water will be found to 

 make an effective wash. 



