sometimes carried up with the draught.

A six-celled destructor kiln burns about 42 tons of refuse in
twenty-four hours, leaving about one-fourth of its bulk of clinkers and
ashes. The clinkers are withdrawn from the furnaces five times each day
and night, or about every two-and-a-half hours, into iron barrows, and
wheeled outside the shed which covers the destructor, and when cold are
wheeled back to the mortar mills, of which there are two at each depot,
each having a revolving pan 8 feet in diameter, with 27-cwt. rollers,
the pan making twenty two revolutions a minute. Forty shovelfuls of
clinkers and twelve of slaked lime make 7 cwt. of mortar in thirty-five
minutes in each pan, which is sold at 5s. 6d. per ton. The engine
driving the two mortar mills has a 14 inch cylinder, 30 inches length
of stroke, and makes sixty revolutions per minute with 45 pounds steam
pressure per square inch in the boiler, when both mortar mills are
running. The boiler is 11 feet long, 8 feet in diameter, and has 132
tubes 4 inches in external diameter, which, together with the external
flues, are cleaned out once a month.

At first sight it would probably appear that no good mortar could be
made from such refuse as has been described, but having passed through
the furnace, the clinkers are, of course, perfectly clean, and with good
lime make a really strong and excellent mortar. They are also largely
used for the foundation of roadways.

The number of men employed is as follows: Two furnace men in the daytime
and two at night. They work from midnight on Sundays to 2 P.M. on
Saturdays, the fires being fully charged and left to burn through the
Sundays. One foreman, who attends also to the running of the engine, and
one mortar man. A watchman attends while the workmen are off.