Report of the Trials of Ploughs, Harrows, ^-c., at Hull. 571 
The frame carrying the mouldboards revolves upon a central bearing, which,, 
being hollow, allows of a rod passing through it, terminating in a short chain, tO' 
the vertical shaft of the fore-wheel carriage. The other end of this rod is 
connected, by another short chain, with a movable wheel under the stilts, 
which during work occupies a forward position. This wheel is also attached 
to a spring which acts as a lock upon the frame. The workman, by means of 
a lever-handle attached to the standard of this wheel, brings it into a vertical 
position, in which it is held by two small spuds or spikes. By this move- 
ment the frame is set free to revolve, and the fore part of the plough is- 
raised clear of the ground. The frame is turned round by the workman, and, 
being well balanced, this is effected with the greatest ease. The stop on the 
furrow-wheel is turned over by the same movement, being attached to the 
frame by a small chain, and the fore-wheels assume a level condition. And 
now comes into play the most ingenious part of the whole, viz. the self-acting 
shoe, which, as soon as the ploughs are raised out of the ground, drops down 
by its own weight, and takes a bearing just about in the centre of the machine. 
As soon as the ploughs are reversed the workman slightly raises the handles, 
thereby setting free the hind -wheel, which, acted on by the spring and the 
strain from the rod, flies back to its position under the beam. The beam assumes 
its parallel form, and the ploughs would be upon the ground but for the self- 
acting shoe, on which and the fore-wheels the whole frame is carried clear of 
the ground. The shoe, formed of a small disc wheel bolted to its arm, 
revolves, consequently the plough rides round, as it were, on a pivot ; and as 
the share enters the ground the shoe is pushed back, and remains clear 
of the soil behind the second mouldboard. Fig. 60 shows the position of 
the shoe during work ; it will be 
evident that, as soon as the frame Fio". 60. 
is raised from the ground, the shoe 
will come forward and take a bear- 
ing on the ground. This I have 
endeavoured to show by the dotted 
lines. The arm of the shoe is 
attached to the central bearings. 
The plough is made entirely of 
wrought or malleable iron. The 
horse-track is sufficiently wide, 
there being 16 inches from the slade 
to the widest part of the mouldboard. 
The hind-wheel is regulated by <.-o"^ 
an adjusting screw. The right- 
hand beam is adjusted by means of a slot in the transverse jjiece, so that the 
width of furrow admits of considerable variation. It should be noticed that on 
these transverse pieces at the fore end of the beam are two studs for the purpose 
of locking the frames on to the central beam ; and, to further render it impossible 
for any sudden shock to sever the connection, a key or stud is applied to the 
hind transverse piece, and acted upon by a spiral spring secured to the central 
beam by a collar or set screw. This will be best understood by reference to 
the plan of the frame. Fig. 66. It will be seen from this arrangement that the 
tension of draught increases the rigidity of the frame. The work done was of 
a superior character, and, considering the extra weight of the plough, the 
draught was not excessive. 
It is hoped that the figures on p. 572 will convey a clearer imi3rcssion of 
the nature and construction of the double-furrow turn-wrest plough than is 
possible from description only. 
Fig. 61 shows the position of the back wheel and leverage during work. 
The rod a, passing through the central tube, indicated by dotted lines, is- 
connected with the fore-carriage by a bell trap lever b. The hind end of the 
