drive the invaders back to their ships; but in proportion as the facilities of communication and the population increased, the defenses on the land side were reduced to a minimum. Between 1812 and 1884 the transition from sail vessels to steamers and from stage coaches to steam cars, and the increase of population to fifty millions, developed such ready means of throwing large forces upon threatened points that a hostile debarkation with the view of capturing our forts by a regular siege on land is not considered practicable. This secures to us the advantage of being attacked only by ships, and our forts and batteries need protection on the land only sufficient to prevent a successful attempt from boating parties to take them in rear by surprise, for the purpose of spiking and disabling the guns and blowing up the small magazines intended for the service of the guns. This point needs to be somewhat dwelt upon as a reply to the reckless assertion that there is a sinister motive underlying the recommendations for forts and batteries for the defense of our harbors; that these may be intended to overawe our cities, and their construction also made a pretext for a large increase of the standing army to destroy the liberties of the country. We have already seen that the system adopted almost dispenses with defense on the land side, so that the citizen soldiers from the cities could easily take possession of the forts, and, as to any needed increase of the standing army, a small fraction of the present force, easily disposable during a time of peace, would suffice to take care of all the forts. In time of war our system requires the garrisons of these forts to be composed almost entirely of citizen soldiers. In former times the forts were placed near our cities; at present the engineers are moving them far down the harbors to the greatest distance from the cities that the defensive features of the neighborhood will permit, and it is considered advisable to place them not less than 7 miles from the places to be defended. These sea-coast forts do not surround the cities like the fortifications of Paris, which are held up by the alarmists as a warning, but simply defend the narrow channels leading to the harbor. It is apparent from this explanation that the construction of sea coast batteries will have no effect in overawing the cities, increasing the standing army, or impairing the liberties of the people." The engineers have uniformly considered that batteries of cannon alone could not generally close the water approaches to our harbors against the ingress of hostile fleets, and their earliest reports contain recommendations for the placing of obstructions in the channels, as rafts, piles, sunken hulks, &c., to arrest and hold them under the fire of our guns. The passage of the forts at New Orleans by Admiral Farragut was not attempted until after the obstructions moored in the channel by the Confederates had been broken up and sent adrift by the floods of the Mississippi. The present system, by the use of torpedoes-that is, submarine mines anchored in the channels-enables the defense to stop the ingress of hostile fleets until the mines shall have been removed, or, at least, the means of exploding them destroyed. These mines consist of a shell of iron inclosing a charge of dynamite, gun-cotton, or explosive gelatine, and are so arranged as to make it impossible for a vessel to enter without touching one or more. The explosion is regulated by electric currents communicated from the shore through cables, so as to take place from simple contact of the vessel with the torpedo, or by the act of the electrician, as he may choose; so that a friendly vessel shall pass over unharmed, while that of an enemy immediately following would be destroyed. But unless these lines of torpedoes are defended by guns of such power as to pierce the armor of iron-clads, they may be countermined and removed with impunity, or the cables and other electrical communications may be dragged for and the whole system rendered innocuous. The rooms which contain the electric apparatus and whence the cables start, as well as the tunnels through which these pass into the water and communicate with the mines, require to be shot and shell proof, for a solitary missile penetrating either the operating room or the cable tunnel might destroy electric connection with the mines and render the entire system useless. A system like this, well managed and defended against hostile attempts, of necessity closes the harbor against an enemy's vessels. What is needed is an amount of funds sufficient for the purchase of torpedo cases, electric cables, and apparatus for all the principal harbors at least-these cases to be kept in store ready to be filled with explosives, and moored or planted in the channels when needed. Another kind is the fish torpedo, operated from shore stations, whose motive-power and steering are effected by electrical connections from the land; this would be mainly used against vessels engaged in attempting to remove the groups of submarine mines already noted. This kind may be very useful, but the other system, that of submarine mines, is the essential element for closing a channel, as may be clearly perceived by supposing the submarine mines to be dispensed with and our reliance placed solely upon the fish torpedo. The enemy's vessel having no mines to fear under its keel enters the harbor at a great speed of 15 or 16 knots-the fish torpedo starting from the shore and with a speed of about 10 miles, encountering a strong current perhaps, will find it very difficult to strike its object. If the weather be thick or foggy, this description of torpedo would be almost useless. But these fish torpedoes are a patented invention, and such is the energy for a profit from their sale that the agents have been actually able to persuade persons who ought to know better that their torpedo is a more important element in defense than the submarine mine. The resistance of some to all measures for defense of harbors cannot be better exemplified than by their assertions at one time that guns are no longer necessary after the invention of torpedoes, and at another when the purchase of torpedo cases, of which a very large number is necessary, is asked for, they find the objection that an improved pattern may hereafter be found. It is impossible to conceive how an improvement in torpedo cases could ever make a change in the results of a charge of dynamite placed under a vessel's bottom, but with those who are determined to have no defenses any excuse is sufficient. Another plea to dispense with defenses is the well worn one that there is needed only an improvised fort or battery of earth or sand thrown up to meet the emergency. Even with the old-fashioned guns of an early date, such as 18, 24, 32, and 42-pounders, it was found necessary to construct substantial platforms of masonry to support them, and to fasten pintles of iron into this mass of masonry to hold the carriage when the gun was fired, and a considerable time was moreover found necessary for the mass to harden and set. When the 10-inch and afterwards the 15-inch gun were introduced, the platforms of masonry were proportionately increased, and, in addition, magazines for powder and shell were built close alongside to save the transportation of the heavy charges. Now that the weight of the projectile has increased from 500 pounds to 2,000 pounds, and the limit is not perhaps reached yet, in addition to magazines for powder and shell, with lifts to raise the charges, there are required engine and boiler rooms for motive power to load and manipulate the gun, and all of these-magazines, engine and boiler rooms, &c.-must be made shot and shell proof against projectiles capable of penetrating 60 feet of sand, and between 30 and 40 feet of concrete masonry. The persons who tell us to wait for war, and then to improvise a sandheap as a fort, without making any provision of emplacements for the guns or for their service, either assume the people to be profoundly ignorant, or are so themselves. Now that by means of submarine mines the defense can compel the enemy, if he attempts to force his way, to lie under the fire of the land batteries until he can clear a passage through the groups of torpedoes, it is manifest that with the addition of guns of heavy caliber, properly protected in their batteries, the entrance to our harbors can be made impregnable to attack, and in case of disaster, through neglect of making arrangements so manifestly effectual, a terrible responsibility must rest somewhere. Some of the guns on land should at least equal the most powerful afloat on the fleet. The armor on land should be much heavier than that carried by ships. The heavier guns of the batteries should be so protected as not to be reached except by a shot coming through the port. It would be very bad judgment, in order to save a little armor, not to make the more important batteries invulnerable to the fire of the fleet. Iron turrets for the heaviest guns, to secure the maximum field of fire; iron casemates, with ports or embrasures, for the next class of guns; the lighter guns in barbette on disappearing carriages-these, with rifled mortar batteries, would, in general, constitute the defense of the most important harbors. The necessity of complete shelter for the more important guns of a position will be rendered clearer by the consideration that a bombardment of the batteries by the lighter vessels of the fleet, armed with the long-range 8-inch and 10-inch guns of the modern type, which would probably be the first operations of the enemy's fleet, will serve to search out uncovered guns and put them out of service by injuries, at least to the carriages and platforms. The English, through the unfortunate choice at first of the muzzleloading in preference to the breech-loading system, condemned themselves to the use of bores too short to develop the full effect of the gases generated by the combustion of the powder charges. Krupp, by the opposite course, manufactured guns, caliber for caliber, superior in penetration and range. As the English, by multiplied experiments upon guns and armor, attracted at first to a greater degree the attention of the military world, and were for a time at least the prominent authorities upon these matters, it is not surprising that their followers were led into error as to the possible velocities which could be imparted to projectiles, and, as a consequence, to the thickness of cover, whether of iron, earth, or masonry, necessary for protection. This period of delay has passed, and the English have adopted the system of breech-loading and of long bores. It is decided also that the best gun of the future should be built up of steel in concentric tubes, or, as it now seems possible, of steel wire wound upon a steel tube and covered on the outside by tubes or jackets to afford longitudinal strength. The gun of the present design, whether constructed by the one or the other system, will be a structure upon correct scientific principles, and future improvements will be very gradual and will not revolutionize by any great or sudden increase the scale of velocities now given to projectiles. It would appear, therefore, that the time has at length come to be supplied with the best modern type, with the confident assurance that before the list of our armament shall have been completed we will be possessed of guns all of which will be valuable, and a number of them the best that can be manufactured. Thus supplied, and until the present military art shall have passed entirely away, it does not appear possible that great changes in the armament of our forts will be necessary. Those persons are greatly in error who imagine that by diplomatic delays war may be averted until proper preparations for defense can be made. Were we as well prepared as many other nations, this might be true; but while a diplomatic delay of a few months might be necessary for a naval power to commission its ships, it would require a great many years for us to get together modern guns, without reference to constructing forts and batteries for their reception. Past events by no means justify the assertions made that our cotton and grain have become so necessary to the nations that they could not engage in war with us for a short period without the interruption of their supplies of these articles. It seems to be forgotten that a descent upon our coast, to hold our unprotected cities under the guns of a hostile fleet, would consume but a few months, and in the mean time cotton and grain in sufficient quantity might be obtained elsewhere. Let it be well understood that the modern system is to make war sudden, sharp, and decisive, and to make the beaten party pay expenses. It is also said by some that England, which has largely the carrying trade of the world, would be very chary of going to war with us, for fear of depredations upon her commerce by our privateers. During the war of 1812 our Baltimore clippers and other fast sailers did, it is true, distinguish themselves as privateers by their sailing qualities, in comparison to the heavy English merchantmen and men-ofwar. But all is now changed; privateers must be steamers. Where are our fast steamers for these purposes? How long would it take to build them, and might not the war terminate before one was afloat? How many fast steamers might not Englaud put in pursuit of one of ours? England has coaling stations all over the world for her cruisers; where are ours? The infrequent stations at which our steamers might obtain coal would be easy, comparatively, to observe, and ingress or egress to our ships, in many cases, prevented. In short, it is not so sure or easy nowadays, with all the circumstances changed, to make privateering either efficient or profitable. But granting all that is claimed for privateers, let us be thankful for delay and avail ourselves of the opportunity offered to put our house in order by fortifying our coasts, and prepare for the day when we shall have restored our shipping to the just proportions required by our national developments in other ways. Let us remember also that the growth of our shipping and the rivalry with England for the carrying trade of the world has been the cause assigned by some for the favor shown to the Confederates, and for the construction in English ports of their cruisers, which swept our commerce from the ocean and destroyed with it her sole grievance against us. If a future struggle for the supremacy in shipping should result in war, let us at least enter into it with our harbors and cities well protected, so that our merchantmen, and even naval vessels, may have places of refuge without fear of capture at our wharves. Should, however, the evil day come and find us without modern guns, without sufficiency of torpedoes, without fortifications except the sand heap which forms the staple quotation, without emplacements for the guns if we had them, or magazines, or machinery for loading or maneuver, or any facilities whatever for shelter of guns and cannoneers against shells and machine guns, it is to be feared we would not cordially welcome the prophet who, having opposed timely preparations promised that in the supreme moment, when the hostile iron-clads, whatever their strength and power, should approach the harbor of New York, they would be turned back somehow, without explaining how, by "Yankee energy, Yankee skill, Yankee inventive genius." It is to be feared that the first flash of the monster guns would dissipate this oratorical vapor emitted when the danger was far off, and leave the deluded hearers to realize the fate of the blind who follow the blind. The Board of Engineers for Fortifications, under directions from this office, has prepared approximate estimates, contained in its reports herewith of August 6 and August 30, 1884, of the cost of fortifications, including the armaments of modern heavy guns and rifled mortars, for Portland, Boston, New York, Philadelphia, Baltimore, Hampton Roads, New Orleans, and San Francisco; and another estimate, likewise approx. imate, for the preliminary works of earth and masonry (without armor, machinery, and guns) to serve as emplacements for the guns. The total estimate, including armaments, is $53,488,000. The estimate for emplacement of guns, excluding armor, guns, and machinery, is $10,388,000. Although these estimates are approximate, they have been made with care, and it is believed that the fortifications (including guns) of all harbors on the coast of sufficient importance to tempt an enemy can be prepared at a cost not to exceed $60,000,000. For the first time in the development of the modern art of war, the engineer has solved, with mathematical certainty, the problem of closing harbors and rivers against hostile ships, so that the sole question in each particular case would be whether the importance of the place would justify the cost. No doubt is entertained that, with the addition of submarine mines, the estimate above would prove sufficient to render these harbors impregnable to naval attack. It is necessary further to say that at the present day no mystery attaches to the method of constructing turrets and casemates of steel or compound plate, and that the requisite plans may be easily prepared by the engineers. ESTIMATES OF APPROPRIATION REQUIRED FOR 1885-1886. FORTIFICATIONS AND TORPEDOES. For defense of Boston Harbor: Four turrets, exclusive of armor, at $220,000.... For defense of New York Harbor: Three turrets, exclusive of armor, at Narrows, at $220,000... $660,000 $880,000 00 460,000 1, 120, 000 00 |