ught safe, for it was in contact with
the French line which extended eastward along the bank of the Somme
to where the dark fortress of Namur frowned on the steeps formed by
the junction of that river with the Meuse. At that point the French
line bent to the south following the course of the latter river.

Namur was expected to hold out for weeks. Its defence lasted but
three days! As a matter of fact it did not delay the oncoming
Germans a day, for they invested it and drove past in their fierce
assault upon Joffre's lines. Enormously outnumbered, the French were
broken and forced to retreat. They left General French's right flank
in the air, exposed to envelopment by von Kluck who was already
reaching around the left flank. The German troops were ample in
number to surround the British, cut them off from all support, and
crush or capture them all. This indeed they were preparing to do
while General French, owing to some mischance never yet explained,
was holding his ground utterly without knowledge that his allies had
already retired leaving his flank without protection.

[Illustration: Photo by Peter A. Juley.

_Dropping a Depth Bomb._

_From the Painting by Lieutenant Farre._]

When that fatal information arrived belatedly at the British
headquarters it seemed like a death warrant. The right of the line
had already been exposed for more than half-a-day. It was
inexplicable that it had not already been attacked. It was
unbelievable that the attack would not fall the next moment. But how
would it be delivered and where, and what force would the enemy
bring to it? Was von Kluck lulling the British into a false sense
of security by leaving the exposed flank unmenaced while he gained
their rear and cut off their retreat? Questions such as these
demanded immediate answer. Ten years before the most dashing scouts
would have clattered off to the front and would have required a day,
perhaps more, to complete the necessary reconnaissance. But though
of all nations, except of course the utterly negligent United
States, Great Britain had least developed her aviation corps, there
were attached to General French's headquarters enough airmen to meet
this need. In a few minutes after the disquieting news arrived the
beat of the propellers rose above the din of the battlefield and the
airplanes appeared above the enemy's lines. An hour or two sufficed
to gather the necessary facts, the fliers returned to headquarters,
and imm