right through from side to side as recent discoveries have verified.

The ancient Egyptians built extensive tunnels for the tombs of their
dead as well as for the temples of the living. When a king of Thebes
ascended the throne he immediately gave orders for his tomb to be cut
out of the solid rock. A separate passage or gallery led to the tomb
along which he was to be borne in death to the final resting place.
Some of the tunnels leading to the mausoleums of the ancient Egyptian
kings were upwards of a thousand feet in length, hewn out of the hard
solid rock. A similar custom prevailed in Assyria, Mesopotamia, Persia
and India.

The early Assyrians built a tunnel under the Euphrates river which was
12 feet wide by 15 high. The course of the river was diverted until
the tunnel was built, then the waters were turned into their former
channel, therefore it was not really a subaqueous tunnel.

The sinking of tunnels under water was to be one of the triumphs of
modern science.

Unquestionably the Romans were the greatest engineers of ancient times.
Much of their masonry work has withstood the disintegrating hand of
time and is as solid and strong to-day as when first erected.

The "Fire-setting" method of tunneling was originated by them, and
they also developed the familiar principle of prosecuting the work at
several points at the same time by means of vertical shafts. They
heated the rock to be excavated by great fires built against the face
of it. When a very high temperature was reached they turned streams
of cold water on the heated stone with the result that great portions