863) that Lee, confronted by 90,000 Northerners, would
detach Stonewall Jackson with more than half his own force of 43,000 to
attack his adversary in the rear" ("The Science of War"). Surprise was
the chief cause of success in the _First Battle of Cambrai_ (November
20, 1917) when General Sir Julian Byng launched the III. Army at dawn
against the highly organised defensive position known as the
"Hindenburg Line." The wire entanglements in front of this position
were exceptionally deep, and had not been broken by gun-fire. Behind
them the Germans were resting in apparent security and such information
as they were able to obtain by raiding reconnaissances was not
corroborated by the fierce and prolonged artillery bombardment which
was at that time regarded as the inseparable prelude to an attack in
force. The advance was preceded by battalions of Tanks, with Infantry
in close support, and was followed by Cavalry, to round up fugitives
and disorganise reinforcements. The artillery had previously been
strengthened and was directed against the support and reserve lines, to
prevent the Germans from massing for counter-attacks and to break up
their formations. Aircraft carried out reconnaissance during the
battle from a low altitude and harassed the defenders with fire action.
An advance was made into the strongest part of the German defensive
system on a twenty-mile front to a depth of five miles, and secured
upwards of 11,000 prisoners, 150 guns, and considerable quantities of
stores and materials, and although after-events neutralised the initial
successes, the advance of November 20, 1917, will ever remain an
example of the value of surprise in war. "Surprise strikes with terror
even those who are by far the stronger. A new weapon of war may ensure
it, or a sudden appearance of a force larger than the adversary's, or a
concentration of forces upon a point at which the adversary is not
ready instantaneously to parry the blow. But if the methods {31} be
various, the aim is always to produce the same moral effect upon the
enemy--terror--by creating in him at the swift apparition of unexpected
and incontestably powerful means, the sentiment of impotence, the
conviction that he cannot conquer--that is to say, that he is
conquered. And this supreme blow of unexpected vigour need not be
directed upon the whole of the enemy's army. For an army is an animate
and organised being, a collection of organs, of which the loss e