48 BULLETIN NO. 3, DIVISION OF ENTOMOLOGY. 
ment of results dependent thereon. The tests showed that with a pipe- 
system, without lateral adjustability at the top, very few rows, usually 
not more than four, can be treated atonce. In this small form the whole 
pipe system can occasionally be moved laterally by hand as the row 
irregularities require it. S 
The forks were operated dragging upon the ground, and also set at 
different heights. ‘he ratchet for vertical adjustment subserved this 
purpose satisfactorily. Where it is desired to spray the base and interior 
of the plants from beneath, the nozzle arms must necessarily be car- 
ried near or on the ground, and with medium to small cotton this method 
also sprays the tops sufficiently well, out if the growth be heavy and 
dense it proves better to set the forks higher for more ren poi- 
soning the tops. 
The stirrer pump worked admirably ; but a larger pump of the same 
kind was necessary to treat a greater number of rows, to ascertain how 
large a number it is possible or advisable to spray atatime. While the 
large pump was being constructed and shipped the time limited by my 
orders expired. 
Four rows may be set as the number it is most practical to treat at a 
time with the kind of machine in question. 
The springs of the fork-arms should be larger and have a longer bend 
than in the samples taken, since the unyielding attachment of the stem. 
pipes to the stiff supporting pipe above throws on the springs much 
greater strain than occurs in the machines having descending parts 
hung to operate independently of each other. 
Until my time had expired worms were not abundant enough to study 
the effects on them of the coarser and finer sprays applied, but the 
coarser spray was more injurious to the foliage with poisons, and still 
more so with petroleum. 
The standard form of eddy-chamber nozzle was used with discharges 
of different sizes. The smallest discharge holes, of ,; to j, of an inch 
diameter, with very high pressure, gave the most Senet results. 
The “ actual cost, and the actual area covered by a given amount of 
liquid,” vary greatly with the width between the rows, the sizes of the 
sprays and of the plants, with the number of nozzles, with the amount 
of pressure applied and the volume capacity of the pump, the velocity 
at which the machine is drawn, ete. On account of the complexity of 
the question, and especially because of leakage from imperfect pipe- 
joints and for want of other and larger apparatus, the question could 
not be solved with any exactness. 
