given to the questions of the lateral
pressure of earth, and he desires to quote here from some experiments
described in a book[F] published in England in 1876, to which his
attention has recently been called. This book appears to have been
intended for young people, but it is of interest to note the following
quotations from a chapter entitled "Sand." This chapter begins by
stating that:

"During the course of a lecture on the Suez Canal by Mr. John H.
Pepper, which was delivered nightly by him at the Polytechnic
Institute in London, he illustrated his lecture by some experiments
designed to exhibit certain properties of sand, which had reference
to the construction of the Suez Canal, and it is stated that though
the properties in question were by no means to be classed among
recent discoveries, the experiments were novel in form and served
to interest the public audience."

Further quotation follows:

"When the Suez Canal was projected, many prophesied evil to the
undertaking, from the sand in the desert being drifted by the wind
into the canal, and others were apprehensive that where the canal
was cut through the sand the bottom would be pushed up by the
pressure on the banks * * *.

"The principle of lateral pressure may now be strikingly
illustrated by taking an American wooden pail and, having
previously cut a large circular hole in the bottom, this is now
covered with fine tissue paper, which should be carefully pasted on
to prevent the particles of sand from flowing through the small
openings between the paper and the wood * * * and being placed
upright and rapidly filled with sand, it may be carried about by
the handle without the slightest fear of the weight of the sand
breaking through the thin medium. * * *

"Probably one of the most convincing experiments is that which may
be performed with a cylindrical tube 18 in. long and 2 in. in
diameter, open at both ends. A piece of tissue paper is carefully
pasted on one end, so that when dry no cracks or interstices are
left. The tube is filled with dry sand to a height of say 12 in. In
the upper part is inserted a solid plug of wood 12 in. long and of
the same or very nearly the same diameter as the inside of the
tube, so that it will move freely up and down like the piston of an
air pump. The tube, sand,