April I 8, 19 1 8 
Land Sc Water 
scheme in the south between Arras and the Oise, with its 
vast expense in men, depend upon a smaller attacking force 
for its conduct. This was by far the most important matter 
from the enemy's point of view. The new offensive, wherever 
it was decided upon, would have to be on a lesser scale than 
the first, and, other things being equal, would have a lesser 
chance of effecting a complete decision. If he were to exploit 
a success here his exploitation would have to be rapid 
because he ha,d already committed himself irrevocably in 
another and distant field to, the use of the great mass of his 
men, to the loss of a great proportion of them, to the pinning 
down of many for the maintenance of an open, greatly in- 
creased, and extended front. 
We shall not understand the battle it all, even the factors 
against us, still less the factors in our favour, unless we 
fully appreciate this point, which I have already emphasised 
but to which I would return. When the enemy dehberatdy 
engaged a month ago in what may properly be called his 
great speculation between Arras and the Oise he banked 
upon i^utting in more than half of his total numerical 
strength, far more than half his real fighting strength, as 
measured not only in numbers, but in the efficiency of units. 
He had thus mortgaged on the speculation of victory there 
the most of all that he had in men and material available for 
attack. He could, of course, draw up very considerable 
reinforcements northwards for a struggle of many days, 5ut 
the whole thing would necessarily be on a reduced scale. 
He also in that deliberately planned hazard prepared to 
lose, and did lose, men upon a scale — measured in numbers 
and time — unprecedented even in this war. He must have 
lost in a fortnight, for immediate purposes at least, more 
than a quarter of a million men, and perhaps nearer a third 
of a million. An even larger expenditure would have been 
justified had it produced the expected rupture between the 
French and the British. FaiUng to produce such a rupture, 
its excess over the expenditure imposed upon the AlUes was 
dead loss ; and, as we know, that rupture was not effected. 
But this is not all. His full measure of success in the 
south, between Arras and the Oise, had put him upon a 
trace of new front far longer than his old one, and also more 
expensive to hold. Nowhere in all that new front did the 
enemy get hold of good defensive dominating positions. He 
failed with very heavy loss to seize the Lassigny Hills ; he 
failed to take the Renaud Hill in front of Noyon ; he failed 
to carry the great glacis which slopes up westward from the 
Avre, and he failed to take the especially important bank of 
high ground west of Albert and the Ancre Valley ; he failed 
to carry the Vimy Ridge on the extreme north. He started 
from a line of 50 miles. He created by his advance a line 
which, in all its sinuosities, is nearly 85 miles in length, and 
on the whole of its vast concavity he was not in any one 
place possessed of a naturally strong defensive position. He 
was everywhere overlooked. All this meant that he would 
be compelled to do whatever he had to do in the north quickly 
and with but a reduced remaining margin of the force he 
could spare for attack. 
As a matter of fact we discovered that even at the moment 
when his destruction of the main defensive zone and his 
passage of the Lys upon the first day, April 9th, had given 
him his great opportunity, he could not throw in, fresh and 
used combined, more thf>n thirty divisions over a period of 
five days. That is a very large number positively, of course. 
It indicates a loss enormously in excess, mile for mile, time 
for time, prisoner for prisoner, and effect for effect, of what 
the French and British offensives cost in the past. Also 
that tremendous expenditure did in this case permit him to 
break through a defensive zone and create for a time a war 
of movement. But relatively, even this great number repre- 
sents action upon a scale nearer a third than a half of that 
upon which the first great effort of March had been designed. 
The Action 
Now let us turn to the details of the action. 
The enemy as he conceived his plan and studied the battle- 
field before him had the following ground to consider : — . 
From above Merville to Armenti^res the little river Lys 
flows through a plain some miles to the north of which nm, 
in a crescent, a series of obstacles : The great forest of Nieppe, 
the slightly rising ground of Bailleul, and its neighbourhood, 
and at last the Messines-Wytschaete heights, which come 
down near to the river again on the east. That plain 
extends south of the rivor for some five miles, up to the 
Aubers Ridge, covering LiUe, where the enemy had his 
observation-posts, and from whence (it is very low) he over- 
looked the scene of his coming attempt. He proposed to 
break through upon the flat from Bethune to Armenti6res, 
seizing Bethune at once so as to cut the final junction there 
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