216 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
than for continuous solid jets with the spray produced externally. Clog- 
ging is also further relieved by the ingoing jet being forced strongly 
across the inner face of the outlet, tending to carry past it any obstruct- 
ing matters, to keep them in motion in the eddy within, as already no- 
ticed with the slot-nozzles having interval rotation. And, here again, a» 
there, a projectile or a body whirling on its axis may be used inside, 
operated by the current to wipe away or disintegrate bodies, which 
would lodge upon the outlet. 
Nozzles made on these principles can be 'applied as nose-pieces to 
screw onto the ends of blast-pipes, and dischaige at an angle, or they 
may be formed to throw the spray directly ahead in the direction of the 
pipe. In Plate XXVI, Fig. 4, is presented a plan-section of this pat- 
tern in a shape it may possess either as a nose-piece or as an entire noz- 
zle. The spout, a, is purposely made very short. It is attached tangen- 
tially to the shell of the chamber, c, from whicb, «, is the discharge. In 
the chamber a partial septum or wall terminating at x to keep the fluid 
from entering the rotation-chamber, until it is completed around to where 
it will sweep across the inner face of the outlet, s. This septum may b« 
immediately inside the outer shell or inside of an inner shell, forming a 
hollow shut-off plug as shown. 
These whistle-jets work well on blast atomizers, and also produce a 
fair spray of liquid, but for the latter purpose it is yet uncertain if they 
can be made to produce a spray equal in fineness to what is thrown by 
the true eddy-jets with central discharge. 
Eddy- jets proper, as a general rule, have the chamber of a circular- 
form, and the jet-hole ought to be at the center of rotation, which may 
vary in some instances from the center of the nozzle. The supply-stream, 
x 1 in the figures already seen, naturally crowds the eddying mass and 
its center of rotation somewhat toward the Fide opposite the inlet. A 
swell can be made on one side of the chamber, as shown in Plate XX I Y, 
Fig. 3, at x, to throw the entrance of the supply-stream outside of a tan- 
gent to the true circle of rotation, which is bounded by the body of th« 
chamber, but the advantages from this are not so great as to prevent 
the simpler circular form from being most generally used. 
A similar feature appears in the nozzle shown as seen from above and 
in profile in Plate XXY, Fig. 7. The chamber has a spiral, conoid con- 
tour, resembling the form of a cone-shell, but with a central apical dis- 
charge. The dotted line shows the inwinding course of the basal margin 
of its side, which leaves a trifacial inlet- passage on the side, x. Th« 
spout, has one end of trifacial shape, and of a size to fit the chamber, 
whicli is partly inserted in its end, and joined to it in the line, x — s. The 
spray produced is of good quality, but is thrown narrower and farther 
than, yet not so fine as, from the flat faced chambers. Nevertheless, 
where the squirting power is only the gravitation from an elevated 
reservoir, or is otherwise limited, cases can occur where the given pres- 
sure does not give or throw fine spray high enough, and nozzles of this 
