If
less heat is desired, the cocks are turned half off. It is not
permissible to entirely extinguish some of the burners, unless the
unused pipes are closed to prevent the products of combustion coming
back into the room. The consumption of gas per burner, full open, with
a pressure of 8/10, is said to be only 4-3/8 cubic feet per hour.
* * * * *
CONCRETE WATER PIPES.
Concrete water pipes of small diameter, according to a foreign
contemporary, are used in parts of France, notably for water mains for
the towns of Coulommiers and Aix-en-Provence. The pipes were formed of
concrete in the trench itself. The mould into which the concrete was
stamped was sheet iron about two yards in length. The several pipes
were not specially joined to each other, the joints being set with
mortar. The concrete consisted of three parts of slow setting cement
and three parts of river sand, mixed with five parts of limestone
debris. The inner diameter of the pipes was nine inches; their
thickness, three inches.
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