in a
system of
sewers, are
the for
forms of
the
of
which they
several classes, the materials
are to be composed, and their relative areas.
64.
form of
The
egg shaped or oval is the
sewer proposed by the Committee,
31.
194
to the action of water. The upper part
should be covered with Concrete, and in no
case should Common Chinese Mortar be
such works
employed for
66.
Dressed
stone cut and well
fitted
would be
the side walls and
may at first
first be
and should be adopted for
adopted for the first and
second classes. There
some difficulty about skilled labor, but
can easily
that can e
65.
not well
be
overcome.
The ordinary Chinese brick is
fitted for heavy works of this
description; but if carefully built, with
really good
mortar, bricks might be
used where rapidity of Construction was an object: but in that case cement should
the lower parts, (inverts and
be used
for sides,) which
are
necessarily most exposed
preferable for
inverts, and the Committee believe would in
the end prove
Classes
more economical for
named
just
Great
the two
care must be taken in their
Construction, with reference to the pressure
to which they may
be liable, and to avoid
deposits in the Sewers themselves, the
fall of
of each individual sewer should be kept uniform throughout as far as practicable.
The areas of the various classes
68
must be based on
the
ate areas of aggregate