[116] REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



to preveut losiug it. In place of the Tvooden stirrer bar formerly employed I have 

 made an iron one having a spring at the middle to clami^ snugly in the eye at the 

 bottom of the pump. This will not weaken with age or break. ^ The cord or chain 

 for pulling out the bar is not essential, as by having the end bung-hole of 2 inches 

 diameter a pair of tongs or pinchers can be inserted to take hold of the end of the 

 stirrer and extract it. The main hose or pipe has a screw union, by which it is 

 easily separable from the pump. 



The descending pipes between the rows should have flexion and torsion in their 

 j oints or segments or hangings. The ground beneath the cotton-rows is highly ridged, 

 and the mid-furrow between each jiair of rows is deep. The ground thus formed 

 operates upon the lower parts of each descending pipe or its appurtenances, when 

 suitably shaped, so as automatically to guide the pipe and its nozzles between the 

 rows, and to follow any crooks therein even when the conveyance is not driven in 

 conformity with such irregularities. This automatical adjusting is allowed to a large 

 extent, even when the top of the descending pipe is firmly or non-adjustably attached, 

 provided that the descending pipe be flexile in some part of its course. This was 

 shown in the earlier flexile forked machines which were tested for this Department 

 near the Atlanta exposition. For the object in question the descending pipe may be 

 flexile throughout, but it is more commonly preferable to construct this pipe of stiff 

 segments having one or two flexile joints, or very short hose segments ; one at. its 

 top, and another at about two-thirds or one-half of the way downward therefrom. 

 It is also generally best to make these flexile segments or joints of three-ply or two- 

 ply hose, and only of such length as to allow them to bend like knee-joints, and to 

 suffer a semi-rotation or semi -torsion. This construction prevents the trailing- fork or 

 other end part from getting turned upside down, or from remaining in wrong attitude 

 after dragging among or over the plants in turning, and it always tends to spring or 

 throw the nozzles back to such positions that they deliver a properly-directed spray 

 into the plants. Where torsion without bending is desired in these*^ flexile places a 

 rod extending through the interior may be employed somewhat as described for cross- 

 pipes and nozzle-arms in the special report of the United States Entomological Com- 

 mission that has been prejjared. The arrangements and constructions referred to have 

 been carefully tested this season to corroborate the results of previous experience. 

 The principle involved is simple and practical in its operation, having been tested at 

 Atlanta, and again this year at Selma, Ala. 



The flexile nozzle-arms of the Y'Sliaped trailing forks, which were originally de- 

 signed with the flexile stems worked satisfactorily thus attached ; but when these fork- 

 arms were tested on a stiffly hung pipe, the spring-rod inside soon proved too weak. 

 The strong pendant T-forks-with curved or sloping side-arms made stiff proximally, 

 and having 3-ply hose for their distal half or two-thirds, stood severe usage by all 

 methods, since they were made of stronger tubing and had much stouter spring-rods 

 within. The spring-rod in each arm had its distal end soldered in a short piece of 

 tube abutting against the stem of the nozzle. Forks of whatever construction will 

 be guided more by the ridges if the arms extend in a somewhat upward direction be- 

 fore becoming horizontal at the ends beneath the plants, as the median part of the 

 fork can then sink into the mid furrow and be guided by its sides. Probably nothing 

 better than the pendant Y-^orks and T -forks can be devised for spraying upward 

 through the center of the xilaut. An additional pair of short arms or of nozzles may 

 be used with advantage to discharge from near the median line in divergent direc- 

 tion upward through the tops of the plants. The simplest i^lan is to join these or 

 the simple eddy chambers directly to the stem-pipe or its extension, low down. Such 

 nozzles may be attached side by side, or in what I call a tandem gang. This is a 

 series of short tubes coupled end to end, each bearing an eddy-chamber discharge. 

 These may be rotated on their axes and so are adjustable to diiferent angles. 1 -^ose 

 who prefer to underspray the top of the plant and care less for its base will find the 

 tandem arrangement by itself the best device for that purpose for throwing from the 

 .ground, though the forks answer as well when elevated, and may also be used be- 

 aeath the base.. 



The eddy-chamber nozzles seem the best sprayers available for applying the poi- 

 Gon. These nozzles have been tested this season with the discharge-hole of various 

 sizes, from one-sixty-fourth to one-eighth of an inch diameter. The smaller ori- 

 fices give the finest sprays conceivable. Indeed, with high pressure, the spray van- 

 ishes into vapor and steam which does not fall, but rises to seek the clouds. From 

 this the damp particles of x)oi8on powder must separate and fall. But with ordinary 

 pressure too tine a spray is not attained. 



With the fine strainer on the suction end of the pump, clogging materials in the 

 water are prevented from entering the pipe system or the nozzles. Additional smaller 

 ..gauze strainers were attached to the ends of the metal tubes in one set of pipes. 

 They keep out dirt, &c., when the pipes are separated, btit may not prove of impor- 

 tance. The proper method is to have a completely closed system, with folding joints 

 that never need to be separated, so the whole can be folded into a small comjsact pack- 



