INSECTICIDES, PREVENTIVES, AND MACHINERY. 457 



the centre of a flat cap over the chamber. The water emerging 

 from this opening under high pressure has a whirHng motion 

 which produces a cone-shaped spray of exceeding fineness, de- 

 pending upon the amount of pressure and the size of the opening. 

 With a good pressure and an opening one-sixteenth of an inch in 

 diameter, a fine mist-Hke spray can be sent a distance of ten feet, 

 and this fulfils as nearly as possible the requirements of an ideal 

 spray. In order that it may reach the tops of ordinary orchard 

 trees, it is necessary that the nozzle should be elevated, and a va- 



FiG. 474. 



Vermorel nozzle and a section to show the working parts. 



riety of means are adopted to attain that end. In some cases, 

 where extensive orchards of large trees are treated, the spraying 

 is done from a tank cart, and sometimes from a little scaffolding 

 built on it. More frequently, on moderate-sized trees, the hose 

 is tied to a bamboo pole from ten to fifteen feet in length, and 

 with this all such trees are easily reached. Instead of a bamboo 

 pole with the hose attached, some farmers use a gas-pipe of 

 proper diameter, to the end of which the nozzle is screwed. 

 This is somewhat lighter, and the slender pipe is more easily 

 managed. But all these are details which the agriculturist can 

 arrange for himself A surprising amount of spray can be ob- 

 tained from a nozzle of this kind with a very small actual expen- 

 diture of liquid ; but where a great deal of spraying is done, two 

 or three nozzles grouped at the end of a larger discharge pipe are 

 sometimes used. The nozzles are so fixed that the spray is sent 

 in all directions, and a very large area is covered by the poison 



