INSECTICIDES, FUNGICIDES, AND SPRAYING 213 



good for spraying work. It should safely stand a pressure 

 of not less than one hundred and forty pounds to the square 

 inch. For spraying tall trees it is absolutely necessary to 

 maintain a pressure of about one hundred and twenty pounds. 

 A number of brands of hose now made will answer these 

 requirements. While it is desirable to use a light hose so 

 that the equipment will be less cumbersome and it will be 

 easier for the workmen to take the lines up the trees, it has 

 been found undesirable to use hose less than one-half inch 

 in diameter. This is the most common size used, although 

 three-quarter inch and one inch hose are also employed. 



Nozzles. — Although the smallest, the nozzle is none the 

 less one of the most important parts of the spraying outfit. 

 It must break up the mixture into the finest particles and 

 send them against the foliage with the greatest possible 

 force. A very fine, mistlike spray is excellent when the 

 object is simply to cover a large surface ; but such a spray 

 has no penetrating power. 



The "Vermorel" nozzle, or some modification of it, is now 

 used by almost all makers of spraying machinery. In this 

 type of nozzle the stream enters a circular chamber tangen- 

 tially, acquires thereby a rotary motion, and issues from a 

 small, central opening on the upper disk of the chamber. 

 The Vermorel nozzle is especially serviceable in spraying 

 medium sized trees when all the foliage can be easily 

 reached. This type of nozzle has a disgorging device for 

 forcing out the obstruction when it becomes clogged. 



The construction of the "Cyclone" nozzle is similar to 

 that of the Vermorel, and has the same uses; but is not pro- 

 vided with any disgorging device. 



The "Bordeaux" nozzle is so constructed that the 

 character of the spray can be changed from a solid 



