Report of the Trials of Ploughs, Hcdtows, Sfc, at Hull. 573 
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rod is attached to the wheel-arm c, the handle of which is shjihtly 
the plougluuan, aud this brings the spikes, d, in collision with tl 
and arrests the progress of the plough ; all 
further labour is taken from the ploughman 
by the onward action of the horses, the plough 
is raised clear of the ground, and assumes the 
position shown at Fig. 62. 
When the frame is thus elevated, the lock- 
ing apparatus is acted upon for unlocking or 
removing the rigidity of the wheels. This is 
efl'ected by the chains 1, 1, shown in Figs. 63 
and 64, which are hooked to the head of the 
plough. As the frame is raised, both locks, 
shown at 2, 2, are drawn up from the studs, 
3, 3 ; by a slight elevation of the stilts, the 
hold of the ground by the spikes of the hind- 
wheel is released ; the wheel springs forward by 
the tension of the rod, as before described, and 
the frame is again let down for the next 
furrow. As it descends, the locks fall into 
their places on the studs, the wheels are im- 
mediately made rigid and adjust the depth of 
furrow required. Thus the locking arrange- 
ment is perfectly self-acting, viz. self-locking, 
self-unlocking, and self-adjusting. Of course 
the under part of the shaft, or axle, of the fore- 
wheel is jointed. 
Fig. 63 shows the lock, as at the headlands, 
unlocked, and held to chains clear of the studs. 
Fig. 64 shows the lock when the plough is 
let down in working position, and the wheels 
are made rigid by the lock falling on the stud, 
each lock acting at alternate headlands. 
Fig. 65 shows the form of the lock. 
In Fig. 66 a plan is given of the central tube, 
springs, and studs, which will assist the reader 
to understand how the plough can be held 
rigid in work : a, the spiral springs ; h, the 
key or studs ; c, the studs. 
For the results of the Dynamome- 
ter Trials see Table II., facing p. 539. 
The prize of 5/. was awarded to this 
plough. 
Class 13. — Subsection G. Double 
mol^ldboards or ridgixg 
Ploughs. 
The conditions attaching to this 
class were that the plough should not 
exceed 2^ cwt., and should be tested (J 
in ridging up land from the flat, 
moulding up potatoes, and opening water furrows after plough- 
ing. I was unavoidably absent during these trials, and there- 
fore do not know the arrangements as to the different tests ; 
