h round steel rods,
and laid above the surface of the ground. The work is planned for two
rows of pipes, each capable of carrying 123 cub. ft. per second; of
these one so far has been laid. The lengths of the pipes at each of
the three canons are 551, 964 and 756 ft. respectively, and the
maximum head at any place is 160 ft. The pipes are not painted, and it
has been suggested that they would suffer in their exposed position in
case of a bush fire, a contingency to which, of course, flumes are
also liable.

New York.

_Aqueducts of New York._--There are three aqueducts in New York--the
Old Croton Aqueduct (1837-1843), the Bronx River Conduit (1880-1885),
and the New Croton Aqueduct (1884-1893), discharging respectively 95,
28, and 302 million U.S. gallons a day; their combined delivery is
therefore 425 million gallons a day. The Old Croton Aqueduct is about
41 m. in length, and was constructed as a masonry conduit, except at
the Harlem and Manhattan valleys, where two lines of 36-in. pipe were
used. The inclination of the former is at the rate of about 13 in. per
mile. The area of the cross-section is 53.34 sq. ft., the height is
8-1/2 ft., and the greatest width 7 ft. 5 in.; the roof is
semicircular, the floor segmental, and the sides have a batter on the
face of 1/2 in. per foot. The sides and invert are of concrete, faced
with 4 in. of brickwork, the roof being entirely of brickwork. There
is a bridge over the Harlem river 1450 ft. in length, consisting of
fifteen semicircular arches; its soffit is 100 ft. above high water,
and its cost was $963,427. The construction of the New Croton Aqueduct
was begun in 1885, and the works were sufficiently advanced by the
15th of July 1890 to allow the supply to be begun. The lengths of the
various parts of the aqueduct are as follows:--

Miles.
Tunnel 29.75
Cut-and-cover 1.12
Cast-iron pipes, 48 in. diameter, 8 rows. 2.38
-----
Croton Inlet to Central Park. 33.25
=====

The length of tunnel under pressure (circular form) is 7.17 m., and
that not under pressure (horse-shoe form) 23.70 m. The maximum
pressure in the former is 55 lb. per sq. in. The width and height of
the horse-shoe form