2Q8 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
like, with a short slit,/, in the middle, while to each side of it the front 
edge is bent upward, more steeply at the center but less and less to- 
wards the outer angles where the common level of the rest of the plate 
is attained and beyond which the margins of the plate roll up. In 
case the water escapes through the central slit badly it may be bridged 
over by a drop of solder on its back. 
The third form, Plate XX, Fig. 1, by which similar results have been 
obtained, is the most satisfactory. In it there are no corners, the front 
edge,/, being rounded and moderately elevated to an angle approximat- 
ing 35°, but more or less variable with the pitch of the impiugent solid 
jet. Although the upturned sides, hh, somewhat condense the outer mar- 
gins of the spray thus made, they are thrown as far as the central part 
because of their encountering less resistance, for the forward margin 
toward the middle retards more and deflects the fluid strongly toward 
the sides. 
The form shown in Plate XX, Fig. 2, with a straight slightly upturned 
front edge, has been used by some in preference to the older style with 
a plate entirely flat; but while it retards the central portion most it does 
not spread this part strongly enough and has the fault of retarding also 
the sides somewhat and deflecting them more than the center, whereby 
they are thrown less distant and made thinner when they ought in- 
stead to be condensed slightly in a lateral direction and be not at all 
impeded in front, for the rule to be established for throwing a d -flector- 
spray of equal quality, density, and distance from tbe center to the out- 
side is to hold or deflect the sides somewhat toward the center, and the 
denser center somewhat toward the sides. 
The nozzle shown in Plate XXI, Fig. 1, was patented by Mr. E. Hoi- 
lings in 1853 (Xo. 9520). The loose ring, o, surrounding and pivoted, at 
ss to, the discharge end of the hose pipe, i>, bears tbe triangular deflector 
plate, A, and the lever, 27, by which the plate may be tilted up or down. 
A spring, c, tends to elevate the lever and depress the plate, but the 
thumb can be used in opposition to the spring to alter the pitch of the 
same at any instant. The same changes can be made more slowly by 
turning up or down the screw, 2), operating upon the lever through the 
link, E E ; but the screw is especially for the purpose of holding the plate 
more steadily at the angle desired and without any manual .effort. This 
device without the screw is presented in the descriptive catalogue (p. 
221, Fig. 159), of Messrs. W. and B. Douglas, of Middletown, Conn., 
with the statement that "Fig. 159 shows hose-pipe with our improved 
sprinkler on it." 
Similar adjustments appear in a more compact and hence more con- 
venient device patented in 1873 (Xo. 142719) by Mr. Amos Xickerson, 
of East Somerville. Mass. In Plate XXI, Fig. 2, the flat plate, B,hasi!s 
lateral margins turned np and is pivoted, at c, to the hose-pipe, A. The 
plate is set at the angle desired by the thumb screw, 2), working through 
it« v >ry short lever arm, at s, and against the pipe, A. 
