Spraying Devices and Machinery. 197 



that dealers considered the matter seriously. The principle 

 underlying the construction of the apparatus is that the move- 

 ment of the piston draws into the cylinder a certain amount 

 of water through one 

 opening, but through 

 a second one kerosene 

 is drawn in. The two 

 liquids become intimate- 

 ly mixed by their pas- 

 sage through the pump 

 before being thrown 

 from the nozzle, and 

 thus a dilute kerosene 

 may be evenly applied. 

 The flow of kerosene 

 into the cylinder may 

 be regulated by a stop- 

 cock. 1 An improved 

 form of such an attach- 



FIG. 17. An improved form of a kerosene reser- 

 voir attached to a knapsack pump. 



inent on a . knapsack 

 pump is shown in Fig. 

 17. The Demiug Co., 

 of Salem. O., and Professor H. E. Weed, of Agricultural Col- 

 lege, Mississippi, have been most active in perfecting these 

 machines. 



II. EVOLUTION OF NOZZLES. 



The production of the spray nozzle is one of the most inter- 

 esting of the many problems which have taxed the ingenuity 

 of inventors. So long as the materials applied were in the form 

 of clear liquids, or when they were used only in small quantities, 

 not much attention was paid to this part of the machines. But 

 with the use of the garden engine and force pump, and more 

 dense fluids, there also arose the demand for proper devices by 

 means of which the liquid thrown could be broken up more or 

 less finely. 



The simplest, and probably the first form of nozzle was one 



* See also Wit. Agric. Exp. Sta. Ann. Sept. 1891, 162, and Garden and 

 Forest, vii. 1895, 143. 



