But all that was in nineteen-fifteen. In warfare your best teacher is your opponent. Nowadays we have, on each side of No Man’s Land, assimilated one another’s methods. Moreover, trench warfare of to-day has developed into a fluid affair. For one thing, trench-mortars, tanks, and intensive artillery bombardments can make hay of the most elaborate defensive works. You can no longer surround yourself with barbed wire and go comfortably to bed, secure in the knowledge that your opponent cannot possibly get at you without a long and laborious artillery preparation. In nineteen-sixteen, before the First Battle of the Somme, British and French guns pounded the German trenches night and day for three weeks. It was a great pounding, but it cannot be said that the subsequent attack came as a surprise to the enemy. Under such prolonged and pointed attentions even a German is apt to suspect that something is in the wind. But to-day we have other methods. Three minutes of pandemonium from massed trench-mortars—a rush of tanks—and your defences are gone and the Philistine is upon you. So in nineteen-eighteen we live perpetually upon the _qui vive_, and our methods have been elaborated and standardized to the common measure of our joint experience. Our artillery has the whole front registered. At a given signal it can let down a barrage—a Niagara of shrapnel and high-explosive—upon the strip of earth that separates the enemy’s front line from our own. This can be stationary, to annihilate an enemy attack, or “creeping,” to form a protective screen for an attack of our own. We have machine guns too, set, _à la_ Boche, at fixed angles to maintain a continuous band of fire along each line of our trenches—more especially along the second line; for it is a waste of life and energy to-day to treat the front trench as anything more than a close chain of outposts, screening the real dispositions behind. And the rifle and bayonet have come back to their own. Two years ago they were in danger of being discarded as obsolete. Every one was bomb mad. It was claimed that a rifle and bayonet are useless against an experienced opponent feeling his way along a zigzag trench in your direction. True; but a bomb is equally useless—or rather, equally dangerous—in the presence of an opponent rushing upon you in the open. So now we have adjusted our perspectives, and each device of war is put to its proper use. So much for what the author of that little classic, “Dere Mable,” would describe as “Tecknickle stuff.”