for their carrying capacity, but also for their value as anchorages, and
it was found that the screw-pile was more satisfactory in every way; it
could be put down much more rapidly, it was more easily maintained in a
vertical position, and it could carry satisfactorily any load which
could be placed on it as a support for the track. The 16-in. pipe did
not prove efficient either as a carrier or as an anchorage. These tests
will be mentioned in the detailed description of the work to follow.
Figs. 2 and 3 illustrate the general arrangement and details of the
machine designed by the writer and used for sinking the test piles in
the tunnels. This machine had been used originally on the New Jersey
side on the test pile at Pier C, and the adaption was not exactly as
shown on these drawings, but if the screw-piles had been placed in the
tunnels, the arrangement shown would have been used.

Surveys, soundings, and borings were commenced in the latter part of
1901 on an assumed center line of tunnels which was the center line of
32d Street extended westward.

The soundings were made from a float stage fastened to a tugboat, the
location being determined by transits on shore and the elevation by
measuring from the surface of the water, a tide gauge being continually
observed and the time of soundings and gauge readings kept.

In the river wash-borings were made from a floating pile-driver on which
was installed a diamond-drill outfit of rods, pump, etc. Fourteen
borings were completed in the river. Considerable difficulty was found
in holding the pile-driver against the current, the material in the
bottom being very soft, and several borings were lost owing to the
drifting of the pile-driver. Each boring was continued, and the depth of
several was more than 250 ft. below the surface of the water. The