226 REPORT 4, UNITED STATES ENTOMOLOaiCAL COMMISSION. 



brushes throw the poisoned liquid as a spray from the cups. I have 

 not seen the operation of this machine, but judge from a similar device, 

 arrived at independently and experiuiented with, that it contains a 

 princii)le which in a modified form will be of some value in poisoning 

 cotton-insects. 



The following statement should be appended here. In speaking of 

 the means of applying Paris green in water to the cotton crops, Dr. 

 George E. Gillespie, of Natchitoches, La., reports : 



"The mode of applying it differs according to the means of the planter 

 using the poison. Many persons make brooms of mayweed [Anthetnis 

 'COtula), which are handy and very convenient -, others use the common 

 garden watering-pots." — Bull. No. 3, p. 125. 



Rotated recesses. — These-, in the ends or sides of rotated bodies, 

 anay be used to throw liquids and powders in a centrifugal manner. 

 ^Vhere such devices whirl very rapidly it is difficult to feed them satis- 

 factorily upon the periphery, and I found of most value a sheet-metal 

 funnel with internal radiating septa. This is rotated rapidly while sup- 

 plied inside with a drijjping stream. 



After devising and using simple apparatuses to test the spraying 

 powers of rotary throwers of the various kinds noticed in thi-:5 chapter, 

 I concluded that another class of machines was superior, and hence 

 stopped the study of such throwers to take up that of blowers, which 

 follows. 



III.— BLOWERS OF POISON. 



Poisonous gases, vapors, liquids or powders, as insecticides, can be 

 ;applied by means of various blast-discharging or blowing devices, and 

 •examples of apparatuses for such purposes will be noticed below. 



ROTARY BLOWERS OF POISON. 

 [Plates XXVIT, XXVIII, XXIX.] 



In order to show the efficiency of rotary fans for blowing poison I 

 designed several different styles, including simple machines to be worked 

 by hand, as well as a compound one for horse-power. Most of those 

 made and tested proved successful. 



The power required to drive one of these fan-blowers is so slight 

 that the lightest band-wheels and gears will answer, and when oper- 

 ated by hand only the slightest effort is necessary. The velocity needed 

 is rapid, yet not exceedingly high, but should i)referably equal one 

 thousand revolutions or more per minute. The difficult part of this 

 problem x)ertained to the devising of a practical method of feeding 

 powder or fluid by a regular and gauged supply in small quantity into 

 the blast in the encasement or spouts of such blowers, and to the pro- 

 duction of suitable distributors to deliver the laden blast upward into 

 the i^lants in a simple and efficient manner. With reference to the kind 



