in the landscape. At the crossing of the river Weaver, 100 ft. wide
and 15 ft. deep, the three pipes, here made of steel, were connected
together laterally, floated into position, and sunk into a dredged
trench prepared to receive them. Under the river Mersey the pipes are
carried in a tunnel, from which, during construction, the water was
excluded by compressed air.

Denver.

_Denver Aqueduct._--The supply to Denver City, initiated by the
Citizens Water Company in 1889, is derived from the Platte river,
rising in the Rocky Mountains. The first aqueduct constructed is
rather over 20 m. in length, of which a length of 16-1/2 m. is made of
wooden stave pipe, 30 in. in diameter. The maximum pressure is that
due to 185 ft. of water; the average cost of the wooden pipe was
$1.36-1/2 per foot, and the capability of discharge 8,400,000 gallons
a day. Within a year of the completion of the first conduit, it became
evident that another of still greater capacity was required. This was
completed in April 1893; it is 34 in. in diameter and will deliver
16,000,000 gallons a day. By increasing the head upon the first pipe,
the combined discharge is 30,000,000 gallons a day. An incident in
obtaining a temporary supply, without waiting for the completion of
the second pipe, was the construction of two wooden pipes, 13 in. in
diameter, crossing a stream with a span of 104 ft., and having no
support other than that derived from their arched form. One end of the
arch is 24-1/2 ft. above the other end, and, when filled with water,
the deflection with eight men on it was only 7/8 of an inch. A
somewhat similar arch, 60 ft. span, occurs on the 34-in. pipe where it
crosses a canal. Schuyler points out (_Trans. Am. Soc. C.E._ vol.
xxxi. p. 148) that the fact that the entire water supply of a city of
150,000 inhabitants is conveyed in wooden mains, is so radical a
departure from all precedents, that it is deserving of more than a
passing notice. He says that it is manifestly and unreservedly
successful, and has achieved an enormous saving in cost. The sum saved
by the use of wooden, in preference to cast-iron pipes, is estimated
at $1,100,000. It is perhaps necessary to state that the pipe is
buried in the ground in the same way as metal pipes. The edges of the
staves are dressed to the radius with a minute tongue 1/16 in. high on
one edge of each stave, but with no