s are supported upon porcelain insulators.

[Sidenote: _Conduit
System for
Distribution_]

From the power house to the subway at 58th Street and Broadway two
lines of conduit, each comprising thirty-two ducts, have been
constructed. These conduits are located on opposite sides of the
street. The arrangement of ducts is 8 x 4, as shown in the section on
page 96.

[Illustration: EXTERIOR OF SUB-STATION NO. 11]

The location and arrangement of ducts along the line of the subway are
illustrated in photographs on pages 98 and 99, which show
respectively a section of ducts on one side of the subway, between
passenger stations, and a section of ducts and one side of the subway,
beneath the platform of a passenger station. From City Hall to 96th
Street (except through the Park Avenue Tunnel) sixty-four ducts are
provided on each side of the subway. North of 96th Street sixty-four
ducts are provided for the West-side lines and an equal number for the
East-side lines. Between passenger stations these ducts help to form
the side walls of the subway, and are arranged thirty-two ducts high
and two ducts wide. Beneath the platform of passenger stations the
arrangement is somewhat varied because of local obstructions, such as
pipes, sewers, etc., of which it was necessary to take account in the
construction of the stations. The plan shown on page 98, however,
is typical.

The necessity of passing the cables from the 32 x 2 arrangement of
ducts along the side of the tunnel to 8 x 8 and 16 x 4 arrangements of
ducts beneath the passenger platforms involves serious difficulties in
the proper support and protection of cables in manholes at the ends of
the station platforms. In order to minimize the risk of interruption
of service due to possible damage to a considerable number of cables
in one of these manholes, resulting from short circuit in a single
cable, all cables except at the joints are covered with two layers of
asbestos aggregating a full 1/4-inch in thickness. This asbestos is
specially prepared and is applied by wrapping the cable with two
strips each 3 inches in width, the outer strip covering the line of
junction between adjacent spirals of the inner strip, the whole when
in place being impregnated with a solution of silicate of soda. The
joints themselves are covered with two layers of asbestos held in
place by steel tape applied spirally. To distribute the strains upon
the cables in manholes, radical supports of var