e wash of the streets, is entirely dependent on
the outlet sewers, and can be effective only when these are so constructed
as to afford a free outfall for the matters that it delivers to them. In
many towns, owing to high situation, or to a rapid inclination of surface,
the outfall is naturally so good as to require but little attention. In
all cases, the manner of constructing the collecting drains is a matter of
great importance, and in this work a radical change has been introduced
within a few years past.

Formerly, immense conduits of porous brick work, in all cases large enough
to be entered to be cleansed, by hand labor, of their accumulated
deposits, were considered necessary for the accommodation of the smallest
discharge. The consequence of this was, that, especially in sewers
carrying but little water, the solid matters contained in the sewage were
deposited by the sluggish flow, frequently causing the entire obstruction
of the passages. Such drains always required frequent and expensive
cleansing by hand, and the decomposition of the filth which they contained
produced a most injurious effect on the health of persons living near
their connections with the street. The foul liquids with which they were
filled, passing through their porous walls, impregnated the earth near
them, and sometimes reached to the cellars of adjacent houses, which were
in consequence rendered extremely unhealthy. Many such sewers are now in
existence, and some such are still being constructed. Not only are they
unsatisfactory, they are much more expensive in construction, and require
much attention and labor for repairs, and cleansing, than do the
stone-ware pipe sewers which are now universally adopted wherever measures
are taken to investigate their comparative merits. An example of the
difference between the old and modern styles of sewers is found in the
drainage of the Westminster School buildings, etc., in London.

The new drainage conveys the house and surface drainage of about two acres
on which are fifteen large houses. The whole length of the drain is about
three thousand feet, and the entire outlet is through two nine inch pipes.
The drainage is perfectly removed, and the pipes are always clean, no foul
matters being deposited at any point. This drainage has been adopted as a
substitute for an old system of sewerage of which the main was from 4 feet
high, by 3 feet 6 inches wide, to 17 feet high and 6 or 7 feet wide. The
ho