APPLIANCES 17 



matter of importance, and whenever a nozzle becomes 

 worn, so as to give too coarse a jet of liquid, a new 

 one should be substituted for it. Nozzles designed 

 for dealing with clear liquids, or with those containing 

 solids in a minute state of division, are not suitable for 

 washes containing much lime, for they soon become 

 clogged or worn. A coarser nozzle should be used in 

 such cases, or if the nozzle is adjustable, as some of 

 them are, the opening may be enlarged. There is 

 generally an arrangement for clearing the nozzle 

 whenever it becomes choked. 



Where an exceptionally fine spray is required, a 

 pneumatic sprayer or " mistifier " may be used, from 

 which the liquid, instead of being forced out by a 

 pump, is ejected by means of compressed air. Small 

 hand-sprayers, holding two or three quarts, are made 

 on this principle, and they will be found exceedingly 

 useful for spraying one or two trees, and also for use 

 in greenhouses, and for experimental purposes. They 

 cost about 22s. Larger machines, made on the same 

 principle, are obtainable. 



For spraying on a more extensive scale, more 

 powerful and complicated appliances are required ; but 

 it would be beyond the scope of the present work to 

 enter into a description of them, and any attempt 

 to do so might involve preferential mention of the 

 various engineering firms who devote their energies 

 to this subject. 



Two points which require attention in spraying 

 should be mentioned : the one, that many of the liquids 

 used contain insoluble substances which tend to 

 separate out, either sinking to the bottom, or rising 



