e from 30 to 60 feet
in length and from three to five feet apart on centers.

Forty-six feet below the ground surface (-26 Cairo datum) was laid the
concrete floor of the siphon.

The siphon is divided into four compartments. There are two storm
chambers, measuring 10 by 13 feet each, one normal weather chamber
measuring 4 by 10 feet, and one public utilities duct, measuring 6 by
10 feet. These are inside dimensions. The floor of the siphon is two
feet thick; the roof, one foot nine inches. The whole structure is a
solid piece of concrete and capable of standing a pressure of more than
2,000 pounds to the square foot. Its total length is 378 feet; the
shipway passing over it is 105 feet wide and 30 feet deep.

In the public utilities duct are carried the city's water pipes,
cables, telephone and telegraph wires, and gas mains.

The storm chambers will handle the rainfall of cloudbursts. In ordinary
weather the water will be concentrated through the smaller chamber, in
order to produce a strong flow and reduce the settlement of sediment to
a minimum.

Eight sluice gates, each 6 by 10 feet, open or close the water
chambers. They are operated by hydraulic cylinders of the most approved
type.

For sending workmen inside the siphon to make repairs or clearing away
an obstruction there are eight manholes. Four measure 6 by 13 feet, two
6 by 6 feet, and two 6 by 4 feet.

As soon as the Florida Walk canal can be deepened and a few link-ups in
the drainage system can be made, the entire drainage of New Orleans, in
normal weather and during light storms, will, according to announcement
by the Sewerage and Water Board, be sent through this outlet. During
the occasional cloudbursts it will be necessary to send some of the
drainage into the lake, but this will be rapidly flowing water and will
sweep offshore. It means a great deal to the suburban development of
the city.

A year and a half the siphon was in the making. Preparations for the
structure cost more than $250,000--excavation foundation, etc. The
concrete alone cost $170,000. Machinery and the work of housing and
installing it cost $60,000 more.

Four bascule steel bridges now cross the Industrial Canal. They are the
largest in the city. Three of them--at Florida Walk, for the Southern
and Public Belt Railways; Gentilly, for the Louisville & Nashville; and
on the lake front, for the Southern, weigh 1,600,000 pounds
each--superstructure only. The fourth--at the l