to the Cultivation of the Land. 
203 
f>;round in order to get a bearing superficies at all, this super- 
ficies being greater the deeper the wheel sinks in ; but the rail- 
piece always bears with a large superficies upon the ground, 
so that no matter what weight may be upon it, it is pressed 
into the ground very slightly indeed. The traction-engine 
will accordingly travel over soft and marshy soil, or where no 
roads exist. In the experiment before a Committee of the Board 
of Ordnance, the engine, with a sufficiency of water for a long 
yoking, weighing U tons, hauled a heavy siege-gun (5 tons 
12 cwt.), carriage and tender (2 tons 7 cvvt.), and 16 men (say 
1 ton 5 cwt.), making a total of 18 tons, including the engine 
itself, from the Woolwich Arsenal up Burrage-road toPlumstead- 
common, and down the steep incline to VV aterman's-field in 
return. The steepest part of the ascent is 1 in 10, and of the 
descent 1 in 8. In going up, the wlieels of the gun-carriage 
sank 1 to 3 inches in the bare shingle of the road, but the engine 
was able to haul it, and could also stop in the steepest descent. 
But long journeys have been repeatedly taken, as well as great 
loads drawn along ; the principal wear being in the rail-pieces 
and their attachments, and the consumption of oil and grease 
is very great, but without any special liability of damage to 
the engine itself. Mr. Charles Burrell, of St. Nicholas Iron- 
works, Thetford, Norfolk, manufacturer of the engines which 
have been often exhibited, has recently patented an improved 
method of affixins: the " endless rail ' to the wheels : the angular 
guide-piece is made to work through the rim of the wheel 
instead of being placed outside, and, with the rails and wearing- 
parts, is made of steel, thus obviating the excessive wear and tear 
which has been the chief objection to the invention. 
Messrs. Tuxford and Sons, of Skirbeck Iron-works, Boston, 
have manufactured several traction-engines, fitted with the 
endless rails. These engines will take the most acute turns on 
common roads, describing a circle on an area 30 feet in diameter : 
they have also a remarkably neat friction-box arrangement, by 
which either side wheel can be instantaneously detached from 
connexion with the power, or either wheel tlirown into gear, or a 
greater power given to one than to the other, without tlie least 
shock or jar. The weight, exclusive of water and fuel, varies 
from 12 tons upwards according to size. At Salisbury, and 
again at Chester, besides many other occasions, and in a journey 
from Thetford in Norfolk to London, Mr. Burrell's Boydell 
engine demonstrated its ability to ascend inclines of 1 in 10, and 
even 1 in 8, dragging a load after it, and to be readily guided in 
any direction and backed at will. The performances in culti- 
vation I have alluded to in another part of this paper. Only let 
the item of wear and tear be improved upon, and the endless 
