shown, are in no way comparable.

The following notes and observations are given in connection with the
skin friction and the bearing value of piles:

The writer has in his possession a copy of an official print which was
recently furnished to bidders in connection with the foundation for a
large public building in New York City. The experiments were made on
good sand at a depth of approximately 43 ft. below water and 47 ft.
below an adjacent excavation. In this instance a 16-in. pipe was sunk to
the depth stated, cleaned out, and a 14-in. piston connected to a 10-in.
pipe was inserted and the ground at the bottom of the 16-in. pipe
subjected to a loading approximating 28 tons per sq. ft. After an
initial settlement of nearly 3 in., there was no further settlement over
an extended period, although the load of 28 tons per sq. ft. was
continued.

In connection with some recent underpinning work, 14-in. hollow
cylindrical piles 6 ft. long were sunk to a depth of 6 ft. with an
ordinary hand-hammer, being excavated as driven. These piles were then
filled with concrete and subjected to a loading in some cases
approximating 60 tons. After a settlement ranging from 9 to 13 in., no
further settlement took place, although the loading was maintained for a
considerable period.

In connection with some other pile work, the writer has seen a 10-in.
pipe, 3/8 in. thick, 4 ft. below the bottom of an open cylinder, at a
depth of about 20 ft., sustain in gravel and sand a load approximating
50 tons when cleaned out to within 2 ft. of the bottom.

He has seen other cylindrical piles with a bearing ring of not more than
3/4 in. resting on gravel at a depth of from 20 to 30 ft., cleaned out
practically to the bottom, sustain a measured load of 60 tons without
settlement.

As to skin friction in sand, a case came under his observation wherein a
14-in. hollow cylindrical pile which had stood for 28 days at a depth of
about 30 ft. in the sand, was cleaned out to its bottom and subjected to
hydraulic pressure, measured by a gauge, and sunk 2 ft. into the sand
without any pressure being registered on the gauge. It should be
explained, however, that the gauge could be subjected to a pressure of
250 lb., equal to a total pressure of 7,000 lb. on the piston of the
jack without registering, which corresponded, assuming it all as skin
friction, to a maximum of not more than 78 lb. per sq. ft., but it
should be noted that this included bearing