552 Trials of Traction- Enrjines at Wolverhampton. 
Si inches wide by 4^ inches thiol;. Tlicse tyres are surrounded by a chain of 
steel shoes ; each shoe is as long as the width of the wheel and is 5 inches wide. 
The shoes are turned np at their ends, and the turned-up ends are connected 
to one another by steel links and pins, thus making an endless chain round 
about the indiarubber tyre. At the I'ront end of the engine is the single steering- 
wheel. This is 3 feet 6 inches in diameter, 1 foot 3^ inches wide, and is similar 
in construction, and is provided with a similar tyro and chain to tliose of the 
driving-wheels. The steering wheel is carried in a large wrought-iron fork, 
the spindle of which extends upwards through a strong casting, and is sur- 
mounted by a spur-wheel driven by a pinion, carried on a projecting bracket, 
which pinion is driven by another spur-wheel deriving its motion from a ijinion 
attaclied to the steering-wheel which is carried ,on, but is not connected to the 
shaft of the fork. The driving-seat is very like that of a reaping-machine and 
is carried on springs. To the hand of the steersman ai'e brought, as already 
stated, the two levers for throwing the pinions in and out of gear, and there 
are also brought the reversing and steering handles. The engine is ordinarily 
worked by two men. The fireman stands immediately behind the steersman, 
and has control over the'feed-])ump. There is a canopy over the fireman and 
steersman to protect them from the weather. The water-tank is placed in 
front of the driving-wheels, and extends forward to beyond the steering-wheel. 
It is recessed out to leave room for this wheel, so that the tank in plan view 
is not unlike that of an ordinary locomotive tender having a central opening 
and two horns. When full the tank contains 375 gallons of water. The 
coal-boxes are immediately above the sides of the tanks and hold 12 cwts. of 
coal. The engine is provided with a useful lift-hand pump, to which a hose 
can be attached so as to draw from any source of water that may be met with 
in travelling along the road. 
The whole of the toothed gearing of this engine was of malleable cast iron. 
The working parts were all encased in a species of wrought-iron cupboard 
Avith doors [on three of the sides, allowing of convenient access. For engines 
travelling along a high road we think this casing of the machinery to be 
useful, as rendering the machine less likely to frighten horses. There was 
not any brake. 
This engine was declared at 24-horse-power, at 115 lbs. steam, and 160 
revolutions. The coals consumed were 4'95 lbs. per horse-power per hour, and 
the water evaporated was 6'72 lbs. per lb. of coal ; 2 lbs. 12 ozs. of oil were 
used during the run, = 6'5 ozs. per actual horse-power per day of 10 hours. 
The indicator diagrams, taken from both cylinders, of which a copy is given in 
Figs. 12 and 13, show that the gross indicated horse-power developed was 29"26. 
The consumption of coals per hour for each such horse-j^ower was 4'2 lbs. 
BurreWs S-IIorse-jwwer, TJwjnson^s Patent. — The second engine in this 
Group was Mr. Charles Burrell's 8-horse-i)ower "Pot Boiler," with india- 
rubber tyres. No. 36G1. Price G35Z. The engine had two cylinders, each 
10-inches stroke by G inches diameter, giving a collective area of 72 circular 
inches, or 9 circular inches for each horse-power. Thus, as in the " Suther- 
land," the Bury double-cylinder standard was followed. The cylinders were 
not steam-jacketed. The boiler was of precisely similar design to that of 
Messrs. Ransomcs, Sims, and Head's engine " Sutherland," and of nearly 
identically the same dimensions. The area of the fire-box heating-surface 
was 38 feet ; of the pot, 15'1 feet ; and of the tubes, 67'75 feet — of which, 
liowever, 35'25 feet was in the steam — leaving as the aggregate heating-surface 
in contact with watci-, 85'5 feet. The area of the fire-grate was 5'41 feet. 
The flue area through the tubes was 0-75 foot. 
The framing of the engine and the disposition of the two driving and one 
steering wheel were also similar to that of the " Sutherland." The tank, 
when full, contained 250 gallons. The tank was in the same position as that 
