With the war of 1870, and even for somewhat before it, it was found that the increased range of modern artillery had destroyed the value of these star-shaped earthworks, taking the place of the old walls round a town. One could batter the place to pieces with distant guns. Though the guns within the place were as strong as the guns outside, they were at this disadvantage: that they were confined within a comparatively small space which the besiegers could search by their fire, while the guns of the besiegers could not be equally well located by the gunners of the besieged within the fortress.
So the next step was to produce what has been known as the Ring Fortress. That is, a series of detached forts lying three or four miles outside the inner place of stores, barracks, etc., which you wanted to defend. Each fort supporting the two others next to it on either side of this ring was thought to be impregnable, for each fort was built within range of the two nearest, and on such a model were built Toul, Verdun, Epinal, Belfort, Metz, Strassburg, Thorn, Cracow, and fifty other great modern strongholds.
The theory that these ring fortresses could hold out indefinitely was based upon the idea that the fort so far out from the fortress would keep the enemy’s guns too far away to damage the inner place of stores and garrison, and that the supporting fire of the various forts would prevent anyone getting between them. The three systems—first the stone wall, then the earthwork, then the ring fortress, are roughly expressed in the second diagram.
Diagram II. Mankind at war has always used devices whereby he has been able with a small number to detain the advance of a larger number. Some of these systems are roughly expressed above. 1. The old stone fortress or castle of the Middle Ages. 2. The wall round a town. 3. The earthworks of a fortress of the period 1620-1860. 4. The “Ring” Fortress (1860-1914)—a series of detached forts lying three or four miles outside the inner place of stores, barracks, etc., which it was desired to defend.
Well, the chief lesson, perhaps, of the present war is that these ring fortresses fall quickly to howitzer fire. Each of the individual forts can be easily reduced by howitzer fire. This is concentrated against certain of the forts, which quickly fall, and once their ring is broken the result is equivalent to the breach in the wall of a fortress, and the whole stronghold falls. That is because in quite recent years two new factors have come in: (1) the mobile heavy howitzer; (2) the highest kinds of explosives.
Diagram III. A howitzer is a gun with a shorter barrel than the ordinary gun, and designed not to shoot its projectile more or less straight across the earth, as an ordinary gun does, but to lob it high up so that it falls almost perpendicularly upon its target.
A howitzer is a gun with a shorter barrel than the ordinary gun (and therefore lighter in proportion to the width of the shell, and so to the amount of the explosive it can fire) and designed not to shoot its projectile more or less straight across the earth, as an ordinary gun does, but to lob it high up so that it falls more or less perpendicularly upon its target.
Thus the German 11.2-inch howitzer, of which we have heard so much in this war, has a maximum range when it is elevated to 43 degrees, or very nearly half-way between pointing flat and pointing straight up—and howitzers can be fired, of course, at a much higher angle than that if necessary.