OSCILLATING BLOWERS OF FLUIDS. 243 



Mr. J. P. Stelle, of Oitronelle, Ala., thus described, in his report in 

 1880, a simple device ^hich he had tested : 



' ' It consists of a small, round tin box affixed upon the pipe of a common hand-bellows, 

 the box sitting at right angles with the pipe. The top is perforated with nnmerous 

 fine holes. London purple undihited is to be placed inside the box and forced up 

 tkrough the perforations by working the bellows." 



Its poor feature is that wetness can enter the perforated face to af- 

 fect the powder, and the outlets may clog, for the best time to apply dry 

 poison thus is when the plants are wet. 



Several small hand-blowers are in the market, but most of them are 

 adapted only for killing bed-bugs and insects on house plants. 



OsciLLATiNa Blowers of Fluids. — This application of the bel- 

 lows promises to be of much importance. It affords the best obtainable 

 blast for atomizing and blowing fluids. The blast atomizers I have de- 

 vised and described below make mists of excellent quality and embody 

 what 8eem to be the best methods of charging, directing, and discharg- 

 ing the blast with liquid. 



Special attention should be given to the machines presented in Plate 

 XXXI, Figs. 7 and 8, and in Plate XXXII, Figs. 4 and 5, described 

 below. 



To prevent the bellows from sucking back (the liquid to be blown to 

 atoms, or the air) from the blast-tube into itself, the blast leaving the 

 bellows is passed outward through an excurrent valve. 



For feeding the blast with liquid to be blown to a spray the devices 

 heretofore used in atomizers for surgical or other purposes are not well 

 adapted to field-poisoning. The principle of blast-suction so commonly 

 employed in them will not lift from large, very deep reservoirs and feed 

 to the blast the supply of liquid required in large machines ; while those 

 which use blast pressure are so constructed as to squirt the liquid of the 

 reservoir upward in opposition to gravity, and to raise it thus out of a 

 large, deep reservoir requires more exhaustion of force to operate the 

 bellows than economy will warrant. And the same will be true when 

 air-pumps are used as described farther on. A much better plan is that 

 in which the fluid gravitates into an automatic feeder or directly into 

 the blast passage, with or without the assistance of blast-pressure or 

 blast-suction. Thus it will be seen that the blast-pipe to be fed with 

 liquid should pass below the level of the liquid, and with this limita- 

 tion may have any position that is convenient. If it pass outside the 

 reservoir one or more conveyor-tubes to or from the blast must be added 

 to communicate with the reservoir. To avoid some comfylication and se- 

 cure greater compactness, with better working, the blast-tube is prefer- 

 ably passed through or against the lower part of the reservoir, from 

 which one or more passages gives the liquid exit into the blast-tube. 

 The quantity to be fed out must be gauged by the size of the outlet or 

 outlets, which may be formed of permanent size, or can be increased, 

 diminished, or closed at will by any adjustable partial or complete shut- 



