cannot be produced under eighteen years. This idea--of
the use of mechanical means to save casualties--undoubtedly had
much to do with the production in the Tank Corps, a new unit and
without traditions, of the very high _esprit de corps_ it has
always shown, and without which it could not have developed
successfully.

"Tanks were first used by the British on the 15th September, 1916,
in the Battle of the Ancre. They had, however, been designed to
meet the conditions which existed _in the preceding year_, before
the tremendous artillery bombardments of the middle stages of the
war reduced the ground to a series of shell-holes and craters,
which were so closely continuous over a large area of ground that
they could not possibly be avoided. Compared with the latest type
of tank, our first effort--known as Mark I.--may appear crude; but
much genius had been expended upon it, and it is worth noting that
both the French and German tanks, produced long after this tank,
were much inferior to it.

"The Ypres salient, let me begin by saying, was never favourable
to the employment of tanks. In the Third Battle of Ypres (31st
July to November, 1917), which I personally believe to have been
the hardest battle of the whole war, the tanks were unable to cope
with the wet and shelled ground."

Nevertheless, towards the end of the Ypres battle the tank attack in
the first Battle of Cambrai was being planned, and there, at last, the
enthusiasts of the Tank Corps had the conditions for which they had
been long hoping--a good ground and a surprise attack.

"It is important to remember, the letter continues, that the
Hindenburg line at that time presented an insoluble problem. The
_sea of wire_ which protected its well-developed trenches and
machine-gun positions was placed almost throughout on the _reverse
slope_ of the hills or rising ground of which the line took
advantage. The artillery observer could hardly get a view of the
wire at all; beside which, it was so deep it would have taken a
month to cut it by artillery fire.

"_The tank provided the solution_--the only solution. The tank, by
_crushing down the wire_--in a few minutes--was able to do what
there seemed no other way of doing. And the tank success at
Cambrai was not a mere flash in the pan. To the end of the war the
Hindenburg line, or