required, by smaller tugs which also returned the empty scows to the
stake.

The unloading plants were similar at the different points, although that
at Greenville was much larger than the others. It included five land
dredges and eight traveling derricks of two types, one floating and the
other mounted on wheels and traveling on a track of 16-ft. gauge. The
derricks handled the large rock, which was loaded at Pier No. 72 by
derricks and telphers. They were of the ordinary A-frame type, and were
designed to handle 20 tons. They were operated by 9 by 10-in. Lidgerwood
double-drum and swinging-gear engines. The large rock was deposited by
the derricks either in the channels along which they worked or in the
fill along shore, without the use of cars. The land dredges were
equipped with a 60-ft. boom and a 2½-yd. Hayward bucket operated by a
14 by 18-in. double-drum Lidgerwood dredging engine. They loaded into
9-yd., standard-gauge, side-dump cars, built by the contractor, and
unloaded the scows to within about 1 ft. of the deck, a Hayward bucket
being unsuitable for closer work without greatly damaging the scows.
The material remaining was loaded by hand into skips which were handled
to the cars by small derricks, one of which was located at the rear of
each dredge. The cars were taken to the dump and returned by 25-ton,
standard-gauge, engines which had previously done service on the
Manhattan Elevated Railroad, but were spotted for loading by the engine
on the dredge.

In order to keep a record of the fleet of scows, which would show the
available supply at a glance, a board, 10 by 15 in., and covered with a
heavy sheet of ruled paper, was arranged as shown by Fig. 10. It was
divided into 12 vertical columns, the first of which was headed "Scows,"
and contained the name or number of each scow in service. The next four