Elements of Military Art and Science / Or, Course Of Instruction In Strategy, Fortification, Tactics Of Battles, &C.; Embracing The Duties Of Staff, Infantry, Cavalry, Artillery, And Engineers; Adapted To The Use Of Volunteers And Militia; Third Edition; With Critical Notes On The Mexican And Crimean Wars.

by H. W. Halleck

The defect referred to by Captain McClelland, and which has so often been pointed out by our best military men, cannot be obviated by any transfer or assignment, whether temporary or permanent, of the appropriate duties of one corps to another. Indeed, such a measure would only tend to make this defect permanent, and to convert a temporary into a lasting evil. It can readily be remedied by legislative action, but in no other way. The executive action suggested would be deprecated by all. Moreover, the evil is now so obvious and so generally admitted, that there can be little doubt that Congress will soon perceive the importance of applying the only proper and effective remedy.

NOTE TO CHAPTER XIII.—PERMANENT FORTIFICATIONS.

Although the general principles of the plan and arrangement of a permanent fortification, as established by the great masters of this branch of military science, remain the same; nevertheless, the vast improvements which have, within the last few years, been made in projectiles, require some changes in the details of defensive works of this character. These changes consist mainly in an increased thickness of stone and earthen parapets and of the covering of magazines, in the arrangement of embrasures, and in protecting the garrison from an enemy's sharpshooters. The introduction of heavier siege guns, and of heavier ordnance on ships of war, and especially on those propelled by steam, require much larger ordnance in forts designed for the defence of harbors. In the Russian war, Sweaborg was made to suffer from a distant bombardment which left her fortifications intact. These modifications in the arrangements and armaments of forts are absolutely necessary in order to restore the relative power of defence against the improvements made in the means of attack. They can very easily be introduced without changing the form or general character of the works, and they are really so very essential that, without them, a fort constructed 25 or 30 years ago, and well suited to the then existing state of the military art, will be likely to offer no very considerable resistance to modern siege batteries or well organized maritime attacks.

Some have gone much further in their estimate of the effect produced by the increased size and force of military projectiles, and boldly assert that masonry works of strong relief can no longer be used, and that the increased range of small arms requires an entire change of the bastioned front, with lines more extended.

With respect to the effect of the increased range of small arms, it is very natural that a superficial observer should adopt the opinion that this improvement must be followed by an extension of the lines of a defensive military work; but a close study of the subject will probably lead to a different conclusion. Such at least is the opinion of the ablest military engineers of Europe. The lines of the bastioned front now generally in use, were really too long for a good defence with the arms in use at the time it was adopted; and, in theory, the "rampart gun" was to be relied upon for the defence of certain exposed points. But this weapon is no longer in use; its place, however, is better supplied by the increased range of the musket and rifle. The latter weapon is almost invaluable for defending the approaches to a permanent work.

With respect to the breaching of stone masonry by siege batteries, it has long been an established principle that all masonry exposed to the fire of land batteries should be masked by earthen works. The neglect of this rule caused the fall of Bomarsund. Those who so readily draw, from the results of that siege, the inference that the present mode of fortifying land fronts must be abandoned, exhibit their ignorance of military engineering. The facts do not justify their conclusions.

With respect to sea fronts, which can be reached only by guns afloat, the case is very different. They are usually casemates of masonry, not masked by earthen works. Whether the increased efficiency of projectiles thrown by ships and floating batteries now require a resort to this mode of protecting masonry on the water fronts of fortifications, is a question well worthy of discussion. This subject has already been alluded to in the Note on Sea-coast Defences, and it is there shown that no facts have yet been developed which require or authorize any change in our present system.

NOTE TO CHAPTER XIV.—FIELD ENGINEERING.

As Mexico had no permanent fortifications to be besieged, the war in that country afforded very little practice in that branch of engineering which is connected with the attack and defence of permanent works, particularly sapping and mining. The only operation resembling a siege was the investment and bombardment of Vera Cruz, and it is worthy of remark that if General Scott had stormed that place, weak as it was, he must have lost a large number of his men, while from his trenches and batteries he reduced it with scarcely the sacrifice of a single life.

Nor did either party in this war make much use of field works in the attack and defence of positions. Nevertheless, no one can read the history of the war without appreciating the important influence which Fort Brown had upon General Taylor's defence of the left bank of the Rio Grande. Again if we compare our loss in other Mexican battles with that which the Americans sustained in their attacks upon Monterey, Churubusco, Molino del Key, and Chapultepec,—places partially secured by field works—we shall be still more convinced of the value of temporary fortifications for the defence of military positions, although it was manifest that the Mexicans neither knew how to construct nor how to defend them.