It has been frequently suggested to me that I write of my experiences at the front. As one of the advance-guard of the American army who participated in the great struggle for freedom long before the United States espoused the cause of the Allies, I am more than willing to do this, owing to my strong desire that the public should know something of the constant fighting which is going on underneath as well as on the surface and above the ground of the trenches both in France and elsewhere, especially if, by so doing, I can help the people at large more fully to appreciate the importance of the work and the unflinching devotion of that branch of the army which but seldom finds itself singled out for the bestowal of special honors or for the expression of public approbation.

This narrative will be mainly concerned with the engineers and sappers who are so quietly and unostentatiously undergoing extraordinary hardships and dangers in their hazardous work below the ground, in order that their comrades of the infantry may occupy them above, safe, at any rate, from underground attack. In no species of land warfare is a cool head and clear brain, combined with decisive and energetic action and determined courage, more required than in the conduct of these military mining operations.

The value of mines and of similar contrivances of the engineer is partly psychological. Though hundreds of men only may be put out of action by their use, thousands of valuable fighting men suffer mentally from the knowledge or from the mere suspicion that their trenches are undermined by the enemy. Such a suspicion causes the strain on their morale to be very severe and their usefulness to be correspondingly diminished.

The men engaged in this work do not receive that inspiration and access of courage which comes from above-ground activity and which enkindles and stimulates enthusiasm, as in a blood-stirring charge. This trench tunnelling and mine laying requires a different form of bravery: that unemotional courage which results from strong self-control, determination, and perseverance of purpose. The personnel of these engineer-mining regiments usually work in twos and threes, or in small groups, cramped in narrow galleries, sometimes 20, sometimes 200, feet below the surface; and often immediately under or beyond the enemy's front trenches. On numerous occasions they silently force their way underground, despite great difficulties and risk, to within a few feet of the enemy sappers, hardly daring to breathe. A cough, a stumble, or a clumsy touch only are necessary to alarm the enemy, cause them to fire their charge, and thus send another party of opposing soldier miners to the "Valhalla" of modern fighting men. In this war, enormous charges of the highest and deadliest explosives known to man are used. Instant annihilation follows the slightest mistake or carelessness in handling such frightful compounds. Always is there excitement in abundance, but its outward manifestation is of necessity determinedly suppressed. No struggle with a living and resourceful enemy comes to stimulate the soldier mining engineer; only a ghostly adversary has he to contend with, one who is both unresponsive and invisible until the final instant.

No part of such work can be hurried. Underground surveys are calmly and efficiently made, huge mine charges deliberately and quietly placed, electrical connections carefully tested, and at the precise moment fired with terrific detonation and damage. The earth is shaken for miles around, trenches are entirely buried with the dÉbris, while companies of men are engulfed, and immense mine-craters formed.

During the progress of this war there has been a constant increase in the number of engineering troops and development in engineer equipment. While the organization of the German troops at the outset of the war included large numbers of engineer soldiers specially trained for military purposes, the number of engineer units in the British forces as well as those of our other allies was comparatively small.

The training of engineer troops among the Allies for use in trench warfare was extremely limited; their work was confined generally to the operations of open warfare.

Trench warfare changed the whole course of events and rendered necessary wide and sweeping changes in organization, training, and equipment. It has been often stated that this is a war of engineers, and it is certainly true. Engineers and engineering problems are found in every branch of the service.

Instead of being a small and comparatively unimportant corps in our great army machine, they are now of the first importance, and no operations of any magnitude are undertaken without including the necessary engineer forces.

In almost every instance careful liaison or co-operation must be effected with the infantry or other arms concerned in the operations.

I can hardly begin to enumerate the different activities of engineers in trench and open warfare. Some of the most important work done by them in this trench warfare includes the construction, repair, and general maintenance of all trenches (assisted by the infantry); the building of all mined dugouts and shelters of all descriptions; the construction of all strong points and emplacements, machine-gun posts, trench-mortar posts, artillery gun-pits, snipers' posts, O.P.'s, or artillery observation-posts, and so on; all demolition work, such as the firing of large charges of high explosives in mines under the enemy's positions, the destruction of enemy strong points, etc.; the building and maintenance of all roads; the construction and destruction of all bridges, construction and operation of light and heavy railroads, and many other duties too numerous to mention.

It is a work of alternate construction and destruction. The sapper must be a real soldier as well as an engineer. With the possible exception of some of the troops on lines of communication, and some railway, harbor, and other special units, they are all combatant troops, and are so rated and recognized. Many thousands of them are on constant trench work and other thousands on work close up, where they are continually shelled and exposed to fire.

The training of the majority of engineers includes the same methods of offense and defense as the infantry, and well it is that it does so. Almost every day on the western front they are called on to accompany the infantry "over the top," or on a raid on enemy trenches; to destroy enemy defenses; or to consolidate captured trenches; or again to "man the parapet" in holding off enemy attacks until infantry reinforcements can come through the usual "barrage." These things happen every day in the trenches, and the engineer soldier would be at a serious disadvantage if he had not been trained in the use of rifle, bomb, and bayonet. No one has a stronger admiration for the infantry than I have, and every one must take off his hat to these "pucca" (real) fighting men, but the fact remains that the sappers who have continual trench duty are subject to the same constant trench fire as the infantry are every day—the only real difference is that they seldom get a chance to "hit" back. They have their work to do, and seldom have a chance to return the compliment and "strafe the Hun," except in self-defense.

Strategists are pretty well agreed that the main successes of the war must be won by sheer hard trench fighting, and continued until the Germans will not be able to pay the cost in lives and munitions.

In this underground warfare the work of the engineers whose business it is to protect the infantry from enemy attacks below ground is both serious and interesting. At the headquarters of the mining regiment a note is opened from the Brigade Staff: "Enemy mining suspected at K 24 b 18—request immediate investigation." An experienced mining officer is at once detailed to proceed to the area in question and report on the situation.

At times it is a question of nerves on the part of some lonely sentry, but quite as often it develops that the enemy are mining in the immediate vicinity. Measures to commence counter-mining are at once started.

Then the game of wits below ground begins. Mine-shafts are sunk and small narrow galleries driven at a depth which the engineers hope will bring them underneath the German attack galleries. From day to day and even from hour to hour when they are within striking distance careful and constant listening below ground is undertaken, both friend and foe endeavoring to make progress as silently as possible.

In a regular mine system all manner of ruses are adopted to keep the enemy guessing as to the exact locality of each of their tunnels: false noises in distant or higher galleries; plain working of pick and shovel in others; meanwhile they are silently and speedily making progress in the genuine tunnels to the real objective.

Often we delay the laying of our charges of high explosive until we are within two or three feet of the enemy gallery and can even hear the enemy miners talking. On three occasions I have heard them talking very plainly, and listened for hours to them working on, quite unconscious of their danger. It was always a source of annoyance to me that I could understand so little German. At other times, and this has happened more than once in the clay soil of Flanders, we have broken into enemy galleries and fought them with automatic pistols, bombs, and portable charges of high explosives.

As a means of offensive warfare, mining has taken an important part, particularly in the launching of infantry attacks and night raids.

The battle of Messines Ridge in July, 1916, was started by firing at the "Zero" hour some 19 mines, spread over a front of several kilometres. In these 19 mines the aggregate of the total high explosive used and fired at the same instant was a few thousand short of 1,000,000 pounds. Some of the individual charges were nearly 100,000 pounds each, and had been laid ready for firing for over twelve months. Some idea of the frightful force and power of these charges may be obtained when it is remembered that each of the "Mills" bombs, or hand-grenades carried by British soldiers, contains one quarter of 1 pound, or 4 ounces, only of this explosive. As a result of this terrific blow the Germans retreated for over a half-mile on the entire front mined, and the initial objectives of the British were captured with astonishingly low casualties.

In counter-mining, when the enemy are met below ground in crossing under No Man's Land, it is the usual practice of the Allies to explode a charge or mine which they call a "camouflet." The camouflet totally destroys the enemy's gallery, but does not break the surface. The common and the overcharged mine always blow a deep and wide cone-shaped crater. Large charges of explosive blow craters several hundred feet in diameter and well over 100 feet in depth.

In almost every sector of the western front in France where the trenches are close together, (that is, from 20 or 30 up to 200 yards apart), these mine-craters are found in No Man's Land. In sectors where mining has been very active, mine-craters are so common that they intersect each other. The "blowing" of a crater in No Man's Land at night and the immediate occupation and consolidation of it by the infantry and engineers is a wonderfully stirring affair. The strain on the morale of the infantry occupying sectors which are known to be mined is a terrible one, especially if they have no engineers to combat the stealthy attack. For the hundreds who are killed, buried, or injured from enemy mines there are thousands who suffer a mental strain from the mere suspicion of their existence.

Trench mining now, I am glad to add, is not the menace that it was in 1915 and 1916, but when the good-weather offensives cease and the usual winter trench warfare is renewed, mining will probably make its reappearance.