284 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



chiefly of interest on account of the features of their distributing pipes, 

 support, means of conveyance, or other accessories. 



One of the oldest devices in our country for throwing liquid poison is 

 a machine thus described by Professor Riley: 



" The Johnson Spray Machine. — This sprinkler, invented by Judge 

 Jehu W. Johnson, of Columbus, Tex. (patents No. 145571, December 

 16, 1873, and No. 145572, of the same date), is not only the oldest one 

 on record for the application of liquid poison on a large scale, but pro- 

 duces the spray in a novel and peculiar manner. 



"The accompanying sketch, [Plate LIII] represents tL is machine in operation. It 

 will be seen therefrom that it consists of a tank placed upon a two-wheeled cart. 

 The pump secured to the top of the tank is a common double-acting force pump, and 

 with the discharge-pipe is connected a transverse pipe. These parts need no further 

 description, and nothing new or peculiar is claimed for them. The claim for the sec- 

 ond patent mentioned above is based upon the addition of a self-acting pitman, the 

 arrangement of which can be seen in the sketch, and which is more fully illustrated 

 [at Plate LIV, Figs. 1 and 2]. The letter A represents the tank, B the platform of the 

 cart, which is provided with the two wheels, C. These are much smaller than ordi- 

 nary cart-wheels, in order to give the required number of revolutions necessary to the 

 successful operation of the pump. In order to place the cart-bed at such an elevation 

 as to pass over the rows of plants, it is raised by means of vertical bars, as will be seen 

 in the sketch. One of the wheels, C,has a crank-pin, c, attached to it, at a suitable 

 distance from the center, and to this crank-pin is attached the lower end of a pitman, 

 the upper end of which is attached to the pump-lever, G. The discharge-pipe of the 

 pump is provided with a valve to regulate the flow of the liquid. With the trans- 

 verse pix)e before mentioned are connected, by means of screw-joints, branch-pipes, K, 

 which in the sketch and in the diagram are five in number. 



'' These branch pipes are made of cast metal, and on their inner surface, at the lower 

 end, grooves / are formed, either during the process of casting or by planing or cut- 

 ting them out afterwards. In the lower end of these branch-pipes a plug made of rub- 

 ber or cork is inserted, and a rod extends from the plug to the upper end of the tube 

 A;, where it engages with a nut by which the plug may be tightened or loosened. It 

 will be seen that the liquid passing through this pipe must escape by way of the 

 grooves and assuttie the form of spray, and that by tightening or loosening the plug 

 the size of the grooves is increased or diminished. 



'^ This machine makes a remarkably fine spray, but it possesses the same disadvantage 

 as those already mentioned, namely, the ease with which the nozzles clog, notwith- 

 standing the receiving-pipe of the pump is provided with a strainer. This I found to 

 be a serious drawback, requiring frequent stopping of the driver and his dismounting 

 to remove, cleanse, and readjust the plugs. The addition of the self-acting pitman 

 has proved less useful than one would suppose, for Judge Johnson himself writes me 

 that ' experience has demonstrated the fact that it is about as easy and far more 

 economical to work the pump by hand-power than to use the j)itman rod.' By dis- 

 pensing with it, the tank may be placed on any cart without special construction. 

 This machine has been considerably used, but its price (|65 without the cart) is very 

 high when compared with that of others here described." 



In this apparatus any suitable force-pump may be used, and no 

 special pump features are designated for it, except that a '' double-act- 

 ing" one is recommended. The arrangement of the pipe to bear nozzles 

 is essential]}^ the same as may be seen in several later machines, nota- 

 bly in those of Mr. Jones, Mr. Binkley, and Mr. Goodin, as described 



