The Tea insects of India. 61 



ease of soap solution the neeesfary temperature may conveniently be 

 obtained by adding it hot off the fire to cold kerosine oiL 



The writer of this report has succeeded in making an excellent emul- 

 sion on a small scale by the simple process of half filling a beer bottle 

 with a mixture of kerosine oil and milk and then setting a cooly to beat 

 it on a pad of cloth. This process, however, is far more laborious than 

 that recommended in the United Slates, where the regular plan is said to 

 be to drive the mixture backwards and forwards for five or ten minutes 

 through the force pump used for spraying the plants. All that is 

 necessary in this case is to insert both the feed-pipe and the nozzle of the 

 force pump into the mixture and then to work the pump until the thick- 

 ening of the fluid shows that the union of the two liquids has been eflPeeted. 



The object of emulsion is to enable the kerosine oil, which is the 

 active insecticide agent, to mix with the water required to dilute it so as 

 to prevent injury to the foliage, The amount of water that should be 

 added varies according to the nature of the plant and that of the insect 

 which it is required to destroy. 



When used carelessly kerosine emulsion is certain to burn the leaves 

 to a more or less serious extent. This is especially the case when hot 

 sunshine follows the application, but can easily be avoided by using the 

 wash in a sufficiently diluted state. Much also depends upon the man- 

 ner in which the application is made, for to obtain the best results it 

 appears to be essential that the spraying should be done with a force 

 pump fitted with ono of the modern ''cyclone " nozzles originally in- 

 vented in the United States Entomological Department. These cyclone 

 nozzles are so arranged that the liquid issues in the form of a fine mist- 

 like spray which envelopes the whole plant and covers every portion of it 

 with the tiniest drops imaginable. This method of application not only 

 makes the same amount of wash go very much further than would other- 

 wise be the ease, but the mist-like spray, penetrating as it does in all 

 directions, is infinitely more effective, so far as killing insects is concerned, 

 than large drops which are almost certain to leave portions of the bush 

 untouched, besides running off on to the ground instead of adhering to 

 the leaves. 



So-called " knapsack force pumps " are now made with a reservoir 

 which can be strapped on to the back of the operator, who thus conve- 

 niently carries a considerable supply of the wash along with him while 

 he sprays the plants l)y means of an aquapult force pump fitted with a 

 cyclone nozzle. Further improvements will no doubt suggest themselves 

 in the form of the apparatus when it comes intq general use upon tea 

 gardens in India. It is important, however, to notice that very satisfac- 

 tory force pumps are already manufactured both in Europe and in 

 4inerica, where they are used for various purposes. 



