required. Consequently the machine works with little power; the one at
the Old Kent Road, which is of the full size for large works, being
actually driven by a one horse power "Otto" gas-engine. Under these
conditions, at a recent trial, two tons of coke were broken in half an
hour, and the material delivered screened into the three classes of
coke, clean breeze (worth as much as the larger coke), and dust, which
at these works is used to mix with lime in the purifiers. The special
advantage of the machine, besides the low power required to drive it and
its simple action, lies in the small quantity of waste. On the occasion
of the trial in question, the dust obtained from two tons of coke
measured only 31/2 bushels, or just over a half hundredweight per ton.
The following statement, prepared from the actual working of the first
machine constructed, shows the practical results of its use. It should
be premised that the machine is assumed to be regularly employed and
driven by the full power for which it is designed, when it will easily
break 8 tons of coke per hour, or 80 tons per working day:

500 feet of gas consumed by a 2 horse power
gas-engine, at cost price of gas delivered s. d.
in holder. 0 9
Oil and cotton waste. 0 6
Two men supplying machine with large
coke, and shoveling up broken, at 4s.
6d. 9 0
Interest and wear and tear (say). 0 3
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Total per day. 10 6
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For 80 tons per day, broken at the rate
of. 0 11/2