61 
The Evohdion of Agricultural Implements. 
Tooth and brush pinion drills (Class 2) have the bottom of 
the seed box pierced with holes, which are covered by a re- 
volving pinion having teeth alternating with brushes, whose 
revolution sweeps out the seed with some approach to regularity : 
but the canting, on hillsides, of the grain to be sown renders 
this drill unfit for use on any but level fields. 
Disc drills (Class 3) are similar to pinion drills, the pinion 
being, however, replaced by a disc having waved edges, which 
alternately open and close the holes in the seed box, bringing 
some seed forward at the same time, just as an endless screw 
might do. These seeders are also unfitted for hillside work. 
In chain drills (Class 4) the seed falls from a hopper on to 
an endless chain, by which it is conveyed to the discharging 
funnel. This drill acts well on hillsides, but has an uncertain 
and irregular delivery. 
Force-feed drills (Class 5), commonly used in America, where 
they were first introduced in 1851, are still regarded with 
distrust by most of the eminent English makers. The bottom 
of each seed-hopper is closed by a small spirally grooved roller, 
which, revolving as the machine advances, su^jplies seed in a 
regular stream to the discharging funnel. The speed of the 
roller is constant, the quantity of seed sown being regulated by 
sliding the feed roll laterally, and thus exposing a greater or 
less length of the feeding grooves. A “ follower,” or blank 
portion of the roll, closes the aperture in the hopper which this 
movement would otherwise occasion. 
Liquid-manure drills (Class 6), first patented by Chandler 
in 1847, are a combination of the cup drill with an apparatus 
for supplying a dose of liquid manure to each portion of seed 
delivered to the furrow. This is accomplished by mounting the 
drill proper on a reservoir of liquid manure, furnished with an 
endless band of cups, which, revolving as the machine advances, 
carry up each a measured quantity of the fluid fertiliser and 
discharge it into the same funnel as that which receives the 
seed, seed and manure thus finding their way together to the soil. 
The difficulty of distributing moist manures has been re- 
cently overcome by a very ingenious drill, the invention of 
Schlor of Vienna. This machine consists of a manure-box, 
carried centrally between two travelling wheels, over the edge 
of which the contents are shed by means of a spindle thickly 
set with spirally-disposed studs. While these revolve the bottom 
of the manure-box rises slowly, causing a thin, even stream of 
manure to fall continuously to the ground. This drill was ex- 
hibited for the first time in this country by Coultas at the 
Doncaster Show, 1891. 
