268 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
across the field and do it well. Including the time spent in filling the barrel it took 
forty-five minutes for each barrel of poison put out; or, in ten hours, three hands and 
four mules would poison about 13 acres." — lb., p. 225. 
Concerning these statements it should be added that (1) in the light 
of more recent improvements by this method the poison is not applied 
" wiih a minimum number of hands " ; (2) the enlargement of the holes 
in rose-nozzles is objectionable as impairing the quality of the spray 
by increasing the quantity of liquid thrown; and (3) if a larger pump of 
the same kind is used to distribute more water, it will not be " with 
less labor," for with the same style of pump the mechanical rule must 
be that the labor varies directly in proportion to the capacity or to 
the quantity distributed. 
It seems that in former reports only the single-acting hand-pumps 
were alluded to or recommended. By looking up everything in the trade 
and in the Patent Office, so far as my time would permit, it has become 
possible to report upon quite a number of others, some of which, as 
noticed above, are double-acting, and hence much preferable to those 
which were formerly represented as the best. 
In this connection it should also be added that although the hydro- 
nettes and fountain pumps are certainly the best hand-pumps, and, in- 
deed, excellent for throwing broadcast sprays from barrels or tanks 
and for applying single jets beneath plants, yet we cannot regard those 
heretofore made as the best barrel-pumps or tank-pumps, since others 
more suitable for such purposes will be noticed more properly under 
the title of ''Barrel and Tank Pumps," further on. 
Finally, it should be added that there are, besides these described, 
other patented modifications in pumps of the above group, but which 
have not yet found the trade to much extent. It is probable that they 
will not compete successfully with those presented above, and in most 
cases they add complication and expense of construction. Their most 
noteworthy features may be briefly noticed in chronological order. 
That by Mr. T. J. Mayall, of Boston, Mass., as patented April 16, 1872 
(No. 125824), has a valve in the discharge end of the piston, and close 
below this a valved suction-inlet through a side-haft to the piston. This 
enables the nozzle to be held steady, and not have a reciprocating 
motion, only the cylinder being slid back and forth. Another patent 
(No. 129750), issued July 23, 1872, to Mr. W. B. Eobius, of No. 1, Upper 
Gordon street, Euston square, Middlesex County, England, Las for its 
most important feature the introduction of an air-chambered coupling 
between the suction-hose of a hydronette and any supply pipe which 
may be connected thereto. Again, in No. 139263, on May 27, 1873, Mr. 
Robins patented the addition of a third or outside concentric cylinder 
with a third valve (of annular form) to provide double suction ; the 
suction being continuous during both strokes of the piston, in single 
acting, or intermittently discharging hydronettes. Also, in No. 154343, 
on August 25, 1874, the same gentleman patented in the piston of a 
