At this juncture let me run over the development of barrage fire as military critics look upon and explain it.
Petain, the great French general, has given expression to one of the outstanding facts of the present war. He says, "The artillery conquers, the infantry occupies." This, in a few words, is the explanation of that new method of attack by "barrage" or, as the English call it, "curtain fire."
This system of attacking the enemy is a new one and has proven most effective for the Allies. In a nutshell, it creates what might be called a danger zone, or, better still, a death zone, just in front of the advancing soldiers. As the soldiers move on ahead the barrage moves on, or it may be more proper to say that the soldiers move just as slowly as the curtain of fire moves, for if they do not, fatal consequences follow. If they should go too fast they would run into the barrage and would be killed by their own artillery, which is in the rear of the trenches. Occasionally a soldier becomes too enthusiastic and goes too fast for the barrage, and then disaster follows. Accuracy, in time and in range, is the one thing which must be most strictly observed by the men who are conducting the barrage hundreds of yards back of the line.
These men project a hail of shells over the heads of their own infantry and across a thin strip of land parallel to the enemy's trench and directed in the first place at his barbed-wire defenses. This line or belt of bursting shells must be so fierce and continuous as to make it impossible for any man to go through it, or at least so perilous and costly to life that no one in his proper senses would try the hazardous experiment. It requires a rapid firing gun for this kind of warfare, and as armies have not had such guns heretofore, of course, the barrage fire was unknown. It is one of the new things that have been evolved during this war. The French soixante-quinze, or "seventy-five millimeter," has been the marvel in gun making which has made this curtain fire possible. It is a gun which shoots very rapidly, which does not displace itself each time it shoots, and which is able to discharge an average of twenty-five three-inch shells every minute without greatly heating up. No gun was ever invented before which could accomplish such a feat.
The older four-inch gun of the French Army, which the seventy-five displaced, could never have shown the efficiency in this direction that the soixante-quinze demonstrates. In the first place its rate of shooting was much too slow, but even if it had been a great deal faster a continuous accuracy was impossible. When it was first aimed its fire could be carefully controlled, but the trouble with it was it threw itself out of place every time it shot. The recoil from such guns is very considerable and the older gun made no provision for it, consequently it had to be aimed all over again every time it was fired because the rebound caused it to dig into the earth and change its entire position. The new soixante-quinze makes careful provision for this factor of recoil and is fitted up like a Ford car with shock absorbers, so that it is ready for the second shot as soon as the first is fired, and for the third as soon as the second is fired. It maintains a fixed position, accelerating very greatly the speed at which it can be fired at any given target. The old four-inch gun fell down just here. The result was that its highest rate of speed was only a quarter of that which could be attained when a field piece was invented, absorbing its recoil and thus leaving its position unchanged. The only limit to the speed of the new gun, therefore, is the rate at which it can be loaded and the degree of temperature it can stand without exploding shells prematurely, but even this latter danger is provided for in this gun, thus keeping it to the minimum. The only elements that prevent absolute accuracy today are slight differences in the shells or perhaps a change of wind, which are, however, practically negligible factors.
Formerly, in the use of the other gun there was the personal variation of the man who aimed the gun quickly, after each shot had displaced or disarranged it, and the other man who assisted him. Each new aiming and shooting of the piece required an absolutely distinct series of movements and thus for every shot there was that much more possibility of error on account of the imperfect coordinating of the two men engaged. In this connection let me say that the curtain fire, which was evolved by the modern quick firing seventy-five, was very soon discovered and quickly adopted and utilized by Germany also.
When first used the purpose of curtain fire was simply to guard or make possible the forward movement of the infantry and was kept well ahead of them, usually one or two hundred yards. It was also uniform all along the line as far as it extended; that is, if it moved ahead a hundred feet at one point it moved the same amount at every other point. It is a ticklish thing at first for men to advance upon the enemy's trenches with their own artillery booming away at their rear and shooting right over their own heads. But the trenches are seldom parallel. Often the country is rough and whereas the enemy may be dug in a hundred yards away at one point, it may be that fifty rods farther down the lines, the trenches are three hundred yards apart. In the main we speak of the lines being parallel, but as a matter of fact they very seldom are so.
During the early days of the war if one of the opponents were going to make an attack he hammered the enemy's position with heavy guns which were concealed or camouflaged perhaps five miles behind the front line trenches. The bombardment lasted until it was assumed most of the enemy's soldiers had taken refuge in the dugouts and were so disorganized that they could not effectively resist. Besides this his trenches would be so battered that the chances of success for the well-planned assault would be the best. The time must be accurately arranged previously. All lieutenants and captains who directed the barrage must keep exact time and have watches timed to the second. My own brother, Brenton, is now a lieutenant of artillery and I had the pleasure of presenting him with a beautiful stop-watch before he went into action.
At the given signal the barrage raised and the doughboys went over the top, hustled down the lanes which had been previously cut in their own barbed wire by the wiring party, made their way across No Man's Land, stooping low as they went, dropping flat to the ground every few yards, and trying to get to the trenches of the enemy before they could be stopped.