r dense atmosphere a
candle when blown out would at once light again. This was before the
days of electric lighting: otherwise we may be sure that that would
have been used, as so many other modern inventions were. For the first
time in any such work, the last pier sunk had telegraphic
communications with the offices on shore; which must have been
comforting to workmen starting out to their labor in the dead of winter
with two weeks' provisions. The dense air of the chambers caused not
only discomfort to the ears, but also in the case of some of the
workmen a partial paralysis. There was no previous experience to go by,
but every precaution seen to be necessary was taken; the hours of work
were made very short, the elevator was provided, medical attendance and
hospital care were given free. After the first disasters no man was
allowed to work in the air-chambers without a doctor's permit. And it
is known that in helping the sufferers with his private means, Eads was
as charitable as ever. Out of 352 men employed in the various
air-chambers, 12 died. Eads, with his wonted generosity of praise,
printed in his yearly report the names of all the men who worked in the
deepest pier from its beginning till it touched bed-rock. It is
interesting to note in passing that of all the workmen in the
blacksmith's yard only the head smith himself could lift a greater
weight than the designer of the bridge.

The superstructure consisted mainly of three steel arches, by far the
longest that had ever been constructed; the first to dispense with
spandrel bracing; and the first to be built of cast-steel. The
"Encyclopaedia Britannica" called them "the finest example of a metal
arch yet erected." They were built out from the piers from both ends to
meet in the middle; and were put into place entirely without staging
from below,--once again, the first instance of such a proceeding. All
the necessary working platforms and machinery were suspended from
temporary towers built on the piers; and thus while the arches were
being put up, navigation below was not interfered with. This throwing
across of the 500-foot arches without the use of false works has been
ranked with the sinking of the piers "through a hundred feet of
shifting quicksands," as producing "some of the most difficult problems
ever attempted by an engineer." One problem, caused by the fault of the
contractors, presented itself when they came to insert the central
tubes to close t