296 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
Machines of the above description but of smaller size do not need 
the legged wheels, but are mounted entirely upon the cart or wagon, 
in which case the cross-bar of the frame rests upon the rear part of 
the vehicle, and the front angle of the frame is attached farther for- 
ward ; but where extremest width is aimed at wheels so close together 
as those of a wagon are objectionable, since their lateral rocking on 
passing upon the row-ridges or other irregularities would cause the 
long arms to be thrown alternately up and down to an undesirable ex- 
tent. This can be somewhat obviated by directing the arms somewhat 
upward, but where greatest expanse is sought wheels farther apart to 
straddle two or more rows will remedy the fault just mentioned. As a 
rule,- smaller machines will probably be used to avoid the extra expense 
of special wheels and legs. And where cotton is uniformly planted, or 
the adjustability is not aimed at, the cross-bar alone, in its simplest 
form, or a pair of the long arms spliced together to extend straight 
across and far off from the vehicle, will, of course, be sufficient with 
any forms of ordinary jointed tubes. Yet there are practical plans 
for altering the pipes on the straight cross-bar to suit row-spaces of 
diverse widths. The first is, to have no intermediate segments joining 
the pipes but have them all radiate from a central source to the bar, on 
which they are adjustably fixed by screw-clamps, hooks, or otherwise, 
and from which they continue parallel onward to their juncture with 
the distal arms. This makes a pipe-system of the smallest number of 
pieces, but it takes more of the tubing than does the segmental con- 
struction. Secondly, the method of employing segments which are ad- 
justable in length can be resorted to. 
The patterns I have made for this arrangement are represented in 
Plate XLIX, Figs. and 10. We may first consider that shown in 
Fig. 0. The metal part with its side branch is indicated by m b. The 
other half of the segment is a piece of hose, h, clamped to the metal 
parts by wire wraps, o, at its ends. It will be seen that the metal 
part telescopes deeply into the hose and the two tubes thus overlap 
concentrically so far that there is a wide range for the adjustment of 
the one upon the other in a back and forth direction to set the section 
thus formed wider or shorter as may be required. As already stated 
above, the hose piece may have inside itself a small rod to give it sup- 
port. The same effect is also accomplished by the design in Plata 
XLIX, Fig. 10, where m b is a smaller half of the segment telescoped 
into w, the larger half, and at /< is a sheath-coupling wired to both at 
oo. The former of the two plans gives a simpler and lighter set of 
tubing. The lightest set of tubes and simplest to make is when only 
hose is used for the segments and all parts except the angle-couplings 
and nozzles, while the flexible parts are sustained by tension or by 
small rods inside. The cost of materials for sets of this kind is not 
greater than for brass tubing, though less durable. Also the cost of 
making is not so great with the rubber ; and then any planter can 
