524 Report on the Trials of Implements at Oxford. 
similar intervals. The chain and india-rubber arc not rigidly connected, but 
can move round independently of each other and of the inner ring which they 
enclose. This is a remarkable fact, and accounts, in some degree, for the 
successful operation, but must cause considerable friction. The steel envelope, 
whilst it materially protects the india-rubber by coming in contact vsdth the 
rougher surfaces, does not materially affect the traction power, because, being 
loose, the plates are flattened down upon the road, and, if we may so express 
it, participate in the elasticity of the rubber. The engine and boiler are 
vertical, being so jilaced on the frame that the weight is principally carried by 
the two hind wheels. A smaller central wheel in front affords the steerage, 
and is remarkably sensitive, the capacity for turning and backing surpassing 
any previous invention. This is principally owing to the reduced surface 
covered by the engine. The form of the boiler allows of gradients of 1 iu 10 
being surmounted. The Judges had the engine moved about the yard, and 
it went out and drew a plough on one occasion ; but, as further experiments 
were impossible, we submit an extract from the Report of Mr. John Anderson, 
Superintendent of Machinery to the War Department, which shows what was 
done under his actual supervision at Leith : — 
" On the first day that I saw it, the streets were wet and sticky to a degree. 
A train of waggons had previously been prepared, containing 10 tons of floui", 
besides their own weight ; they were standing at the bottom of a slippery 
street with a gradient of about 1 in 17 ; to this train the little engine was 
attached, and away it marched as if it had no load, went up to the top of the 
hill, and then down the other side, no breaks being required. It was done so 
neatly, and so much as an ordinary matter of course, that I could not help 
wishing that the War Department had one of them. 
" After depositing its load somewhere in Leith, it was ready for other 
work, so down it ran to the Portobello sea-shore, at the rate of 10 miles an 
hour. On surveying the sands, it seemed an impossibility that it could walk 
on such soft sinking ground ; but on it rushed through all, over some quick- 
sands, ran into the sea, and along its edge in every direction, in the most 
wonderful manner. 
" But this does not convey the true state of the case. I was walking, and 
my feet sank several inches at every step, but the wheels of the engine did 
not sink above one-third of my depth ; and an empty carriage that followed 
on the same track as the engine, with the carriage wheels on the engine track, 
§ank 5 inches deeper. This fact teaches the whole lesson : the carriage wheel, 
being a circle, presented but a small surface, but the flattening of the engine 
india-rubber tires gave a web-footed surface, which explains it all. 
" It is necessary to state that the little engine weighs about 6 tons when 
fully loaded with water and fuel ; the engine cylinders are but G inches in 
diameter, so that when compared with, say the Boydell engine, it is a pigmy. 
" It is used at present in doing any kind of odd work that may be required, 
and well does it earn its living, 
" Its next job, after returning from the sea-side, was to remove an old 
worn-out boiler from the docks to a yard at some distance, where old boilers 
are broken up. The boiler and waggon, with the fastening chains, weighed 
upwards of 22 tons, and the boiler on the waggon stood some 25 feet high. 
Up to this the engine backed, and was securely attached ; then off it marched 
along the quay, over a rising swing-bridge, and along other quays, until it 
reached its destination. But the charm of the above performance was in the 
way in which it was done. No shouting, no refractory or desultory pulling 
of horses ; but by the expenditure of a few pounds of coal and water the 
whole was accomplished with ease and celerity ; and so accustomed are the 
people in Leith to its performance that no notice was taken of it, except by 
the country horses, for the town horses seem to know that it is their friend 
rather than their enemy." 
