CHAPTER IX.
TANKS AND AEROPLANES THE STAFF WORK OF THE WAR I have quoted in the preceding chapter the warning words of Sir Douglas Haig on the subject of "mechanical appliances." The gist of them is that mechanical appliances can never replace men, and that the history of tanks in the war shows that, useful as they have been, their value depends always upon combination with both infantry and artillery.

So far from their doing away with artillery, the Commander-in-Chief points out that the Battle of Amiens, August 8th, in which the greatest force of tanks was used, and in which they were most brilliantly successful, was "an action in which more artillery ammunition was expended than in any action of similar dimensions in the whole war." The tank enthusiasts will clearly not be quite satisfied with so measured a judgment! They point to the marked effect of the tanks on the strategy of the last three months of the war, to the extraordinary increase in the elements of mobility and surprise which their use made possible, to the effect of them also on German opinion and _morale_, and they believe that in any future war--if war there be!--they are certain to play, not a subsidiary, but a commanding part.
One of the most distinguished officers of the Tank Corps, who was wounded and decorated before he joined the corps, was severely wounded twice while he belonged to the corps, and was an eye-witness of the incidents he describes, allows me to print the following letter: "You ask me for a short account of what tanks have done in the war.

In doing so, you set me a difficult problem! For three years I have thought of practically nothing else but tanks, so that I find it very difficult to deal with the subject briefly.

However, I will try.
"The basic idea and purpose of tanks is a very simple one: to save infantry casualties.

A new tank can be built in a few months; a new soldier cannot be produced under eighteen years.