ners cut
their way indomitably towards the goal, though, at every step gained
the work grew more painful and more dangerous.

"The temperature at the face of the heading, had risen from 72 deg
(Fahr.) at the close of the year 1873 to 83 deg during the two following
years; though in the summer of 1875 two powerful Root blowers were
constantly employed in forcing air into the tunnel. At the close of
the year 1876, the indicated temperature was 90 deg and, on the 1st of
January, 1878, the men were working in a temperature of 96 deg.

"In spite of the air currents from the blowers, the atmosphere before
the end of the year 1876 had become almost unbearably foul as well as
hot. The candles flickered with a dull light and men often staggered
back from their posts, faint and sickened.

"During the months preceding the junction with the Savage Mine, the
heading was cut with almost passionate eagerness. The miners were then
two miles from the nearest ventilating shaft, and the heat of their
working chamber was fast growing too intense for human endurance.

"The pipe which applied compressed air to the drills was opened at
several points and the blowers were worked to their utmost capacity.
Still the mercury rose from 98 deg on the 1st of March 1878 to 109 deg on
the 22nd of April, and the temperature of the rock face of the heading
increased from 110 deg to 114 deg. Four shifts a day were worked instead of
three, and the men could only work during a small portion of their
nominal hours of labor.

"Even the tough, wiry mules of the car train could hardly be driven up
to the end of the tunnel and sought for fresh air not less ardently
than the men. Curses, blows, and kicks could scarcely force them away
from the blower-tube openings, and, more than once, a rationally
obstinate mule thrust his head in the end of the canvas air-pipe. He
was literally torn away by main strength, as the miners, when other
means failed, tied his tail to the bodies of two other mules in his
train and forced them to haul back their companion, snorting
viciously, and slipping with stiff legs over the wet floor.

"Neither men nor animals could long endure work so distressing.
Fortunately, the compressed air drills knew neither weariness nor
pain, and churned their way to the mines without ceasing.

"A blast from the Savage Mine tore an opening through the wall, in the
evening of that day. The goal for which Sutro had striven so many
years was in si