War is a thing that changes very rapidly, and we have in the Tanks only the first of a great series of offensive developments. They are bound to be improved, at a great pace. The method of using them will change very rapidly. Any added invention will necessitate the scrapping of old types and the production of the new patterns in quantity. It is of supreme necessity to the Allies if they are to win this war outright that the lead in inventions and enterprise which the British have won over the Germans in this matter should be retained. It is our game now to press the advantage for all it is worth. We have to keep ahead to win. We cannot do so unless we have unstinted men and unstinted material to produce each new development as its use is realised. Given that much, the Tank will enormously enhance the advantage of the new offensive method on the French front; the method that is of gun demolition after aerial photography, followed by an advance; it is a huge addition to our prospect of decisive victory. What does it do? It solves two problems. The existing Tank affords a means of advancing against machine-gun fire and of destroying wire and machine guns without much risk of loss, so soon as the big guns have done their duty by the enemy guns. And also behind the Tank itself, it is useless to conceal, lies the possibility of bringing up big guns and big gun ammunition, across nearly any sort of country, as fast as the advance can press forward. Hitherto every advance has paid a heavy toll to the machine gun, and every advance has had to halt after a couple of miles or so while the big guns (taking five or six days for the job) toiled up to the new positions. 4 It is impossible to restrain a note of sharp urgency from what one has to say about these developments. The Tanks remove the last technical difficulties in our way to decisive victory and a permanent peace; they also afford a reason for straining every nerve to bring about a decision and peace soon. At the risk of seeming an imaginative alarmist I would like to point out the reasons these things disclose for hurrying this war to a decision and doing our utmost to arrange the world's affairs so as to make another war improbable. Already these serio-comic Tanks, weighing something over twenty tons or so, have gone slithering around and sliding over dead and wounded men. That is not an incident for sensitive minds to dwell upon, but it is a mere little child's play anticipation of what the big land ironclads _that are bound to come if there is no world pacification_, are going to do. What lies behind the Tank depends upon this fact; there is no definable upward limit of mass. Upon that I would lay all the stress possible, because everything turns upon that.