The San Francisco call., 1895-11-24

the irrigation drain OF the rivers in South
ern California, these streams have habit
of sinking below the sandy beds in the dry
season. But the river that makes the
boundary between Southern California
exception.
This river, after running through the
most wonderful chasms or system OF
gorges known in the world runs its course
through the Colorado Desert down to the
Gulf of California, in Mexico.
At the foot of the Moiave Mountains,
thirteen miles below the quaint little town
called "The Needless" so named because
at this place there is group of sharp
spires in the Mojave Mountains, the canti-
lo yer bridge crosses the Colorado River,
between Arizona Territory and California.
Travellers bound for the Pacific Slope
crossing the bridge at The Needles are
often informed that they are entering the
lano of sunshine ON the ''longest single
span cantlever bridge in the world, with
one exception Although this is fire.
quently taken as an eXtravagant bit of
local pride, yet it was strictly true when
the bridge was built. Or. James P. Booth,
surgeon of the bridge company, says o! the
cantilever bridge OF the Colorado River,
built in 1890. having a length OF $50 feet,
with single span of 660 feet, that at the
time of its completion it was the Longest,
unsupported bridge span in the world ex-
cepting that of the bridge at the Firth of
Forth" at Queens Ferry, Scotland.
According to the Glasgow Citizen this
bridge is one of the wonders OF the world.
1t has two spans, each of them 100 feet.
The cost was "a 100000.
The first cantilever bridge built in the
TT,,it ta1 hn 1,rf6
built in 1888; at that time it was the first
of any magnitude in the world, the Forth
bridge not having been built. 1t was con-
sidered a marked advance in engineering.
1t may seem paradoxical, but the principle
of the cantilever bridge ls found in the
simplest and earliest forms of bridge
making. Chambers Encyclopedias says:
"The Japanese would lay two balks of
timber. EN- bedding one in one bank and
the other IN the other bank, with the ends
projecting over the stream so as to form
two cantilevers, and would then add a
second balk, reaching from one to the
other" ana that good bridge of this kind
was built in Japan over 1890 years ago."
So much for the simple form or principle
OF the cantilever. The teri term ?, itself Is de-
fined as meaning "bracket."
The long span OF the present system of
the cantilever illustrated in the Niagara
bridge, having total length of $40 feet,
with its single span of 40 feet, according
to the Scientific American, was outrivaled
by the cantilever bridge OF the Colorado,
whose span, as has been noted, was go
feet.
There are other cantilever bridges in the
United States. One is across the Ohio at
Louisville.
According to Dr.. Booth the bridge at
The Needles cost $500 900. OF the manner
of building this bridge he says platform,
called "traveler." went ahead of the
work, carrying material for the construc-
ton of the bridge, and paradoxlcai as 1t
may appear, the bridge was built behind
the traveller" Two iron rails extended
beyond the work, upon which the wheels
of the ..trayeler" rolled, and thus it was
that the '.traveler" was enabled to precede
the bridge itself.
.The building of these bridges is usually
very perilous work and the principal
workmen are experts" DIR. Booth says.
"The management informed me that they
usually lost from eight to twelve men in
the construction of bridge, but in build
ing this bridge there We're but three killed.
One was blown up by premature tlast
of rock, one had heavy iron topple over
and crush him ana the third fell from the
top of the bridge to the ground on the
California side just after the bridge was
begun"
Boats (steamers) pass under the bridge
now during high-water season without
any difficulty, and the expense OF draw
bridge which was necessity with the old
bridge, is entirely done away With.
Is il any wonder that ArlzonlanS ana
Californians join in calling the link that
connects the Territory and the State 1.-The
Great Cantileyer Bridge?"
NJ. BURTON WILLIAMSON,
University, Los Angeles County, Cal.