210 Report on Miscellaneous Implements at Neivcastle, 
shoots. The effect produced by this revolving spiral is really 
surprising. Setting only a small quantity of the mass contained 
in the trough in motion, it persuades the remainder to follow. 
This, no doubt, results from the fact that the impulsion is peri- 
pheral — in other words, that the material is urged forward just 
at, if only at, the point where it is in frictional contact with the 
trough. The quasi-homogeneous character of the mass itself 
does the rest. 
Messrs. Hornsuy and Sons, of Spittlegate Iron AVorks, Grant- 
ham, showed a new Double Furrow Plough (Art. 2,928), having 
an interest of its own, as illustrating the rapidity with which 
the long turn-furrow of the past is giving way to the short 
digging-breast that has always characterised American ploughs. 
After many years of subservience to artificial ideas of what 
a furrow-slice ought to be like, plough-makers are gradually 
returning to the use of short digging-breasts, which, if they do 
not lay a brick-sectioned slice at a prescribed but arbitrary 
angle, at least break up the soil in a way very favourable to 
cropping. This return took effect, first, in simple plouglis, but 
is now spreading to double-furrow ploughs, whose construction 
is vastly simplified by the reform. 
Robert Maynard, of Whittlesford, Cambridge, showed a 
chaff-cutter (Art. 2,956), cutting chaff and litter from | in. to 
6 in. in length. 
Ordinary chaff-cutters experience a difficulty in cutting long 
lengths, because the arms upon which the knives are mounted 
pass in front of the chaff-box, and the issuing straw, unless the 
feed be moderately short, comes in contact with them. 
Maynard evades this difficulty by placing the axis of his 
wheel a little to one side of and high above the chaff-box, its 
periphery being entirely clear of the latter. The knives are 
attached peripherally to removable brackets, and, by using one 
or more knives, combined with suitable changes of the feed 
gear, any length of chaff and litter within the limits mentioned 
can be cut, the straw issuing from the chaff-box finding nothing 
to bar its egress. 
Messrs. Sh irlaw & Co., of Suffolk Works, Birmingham, showed, 
as a novelty, " Spiel's " petroleum engine (Art. 3,054), which 
merits description on the ground of its offering to the farmer 
who is unable to take advantage of that most convenient motor, 
the gas engine, a means of obtaining power witliout a steam 
engine, an advantage which the enormous sale of gas engines 
proves to be both great and general. It is unfortunate that the 
engine shown at Newcastle used petroleum of a volatile cha- 
racter, having a flashing point of too low a temperature to meet 
with the Judges' approval ; but this fact, although properly de- 
