causes the sand to be displaced into them.

The important consideration of this paper is that all the experiments
and observations noted point conclusively to the fact that pressure is
transmitted laterally through ground, most probably along or nearly
parallel to the angles of repose, or in cases of rock or stiff material,
along a line which, until more conclusive experiments are made, may be
taken as a mean between the horizontal and vertical, or approximately 45
degrees. There is no reason to believe that this is not the case
throughout the entire mass of the earth, that each cubic foot, or yard,
or mile is supported or in turn supports its neighboring equivalent
along such lines. The theory is not a new one, and its field is too
large to encompass within the limits of a single paper, but, for
practical purposes, and within the limited areas to which we must
necessarily be confined, the writer believes it can be established
beyond controversy as true. Certain it is that no one has yet found, in
ground free from water pressure or abnormal conditions, any evidence of
greater pressure at the bottom of a deep shaft or tunnel than that near
the surface. Pressures due to the widening of mines beyond the limits of
safety must not be taken as a controversion of this statement, as all
arches have limits of safety, more especially if the useless material
below the theoretical intrados is only partly supported, or is allowed
to be suspended from the natural arch.

The writer believes, also, that the question of confined foundations, in
contradistinction to that of the spreading of foundations, may be worthy
of full discussion, as it applies to safe and economical construction,
and he offers, without special comment, the following observations:

He has found that, in soft ground, results are often obtained with small
open caissons sunk to a depth of a few feet and cleaned out and filled
with concrete, which offer much better resistance than spreading the
foundation over four or five times the equivalent area.

He has found that small steel piles and coffer-dams, from 1-ft.
cylinders to coffer-dams 4 or 5 ft. square, sunk to a depth of only 1 or
2 ft. below adjacent excavations in ordinary sand, have safely resisted
loads four or five times as great as those usually allowed.

He believes that short cylinders, cleaned out and filled with concrete,
or coffer-dams of short steel piling with the surface cleaned out to a
reasonab