2. END VIEW OF CARRIAGE.

1. EIGHT INCH BREECH-LOADING RIFLE ON BARBETTE CARRIAGE. 3. TWELVE INCH BREECH-LOADING RIFLED MORTAR ON SPRING RETURN CARRIAGE.

COAST ARTILLERY.

used in the United States will be found in publications of the War Department, a separate pamphlet for each class of gun, which were prepared for the instruction of artillery gunners. Consult, also, Bruff, Ordnance and Gunnery (New York, 1900), and Drill Regulations for Coast Artillery United States Army, which are published from time to time by the United States War Department.

The construction of coast artillery and other cannon, together with their carriages or mounts, is described and illustrated under ORDNANCE, which should be read in connection with this article, while the historical development of coast artillery as well as of cannon of all forms is discussed under ARTILLERY. The use of coast artillery as a means of defense is treated under the title COAST DEFENSE, where the tactics of coast artillery are described. The forts and other defenses in which coast guns are mounted are discussed in the article FORTIFICATION.

COAST DEFENSE. The defense of a seacoast involves the principles of both strategy and tactics. In considering the principles of strategy applicable to coast fortification it is essential to take into account the navy as our first line of defense. Every nation possessing a coast line has commercial interests, to protect which she requires a navy. Her fleet, whatever its strength, will require points of support on the home coast, to serve as a basis of operation in attack or defense. These points of support contain all the material necessary for building or equipping ships; they furnish all the needed men and supplies to the navy, and must offer for a beaten fleet, or one which on the outbreak of war has not yet completed its equipment, a safe harbor to repair damages or complete equipment. The material of a navy is very expensive and is difficult or impossible to secure after war has begun; consequently, the greater part must be prepared in time of peace and collected at the points of support, for which purpose extensive depots, magazines, and other constructions must be erected. To prevent all these constructions from being demolished at one blow, and to guard the fleet, while still taking in supplies or completing its equipment, against surprise, these points of support must be protected by suitable means, and this is the purpose of fortifications.

The only points of a coast that fulfill the conditions imposed by these considerations are the larger harbors (always bays and mouths of rivers), and they must be fortified not only against attack by sea, but also against land attack, for the late war between Japan and Russia showed conclusively that important naval ports (Port Arthur, for example) may be taken by forces landed on the coast without risking an attack on them by sea.

In applying the principles of land tactics to the selection of sites for, and the construction of, seacoast forts, some modifications must be introduced, due to the fact that the enemy in the latter case is confined to the navigable channels, so that all his possible flanking attempts can be foreseen and provided against. The principles of tactics which find application here are: (1) To obstruct the enemy's advance, while leaving free that of the forces of the defense for offensive movements; in other words, so to obstruct the water approaches against the enemy as to leave free entrance and exit for the defending fleet. (2) To

be superior to the enemy at the point of attack; that is, to bring to bear on the channels of ap proach a heavier fire of high-power guns and howitzers and mortars than any fleet able to operate there can bring to bear on the defenses. (3) To place the isolated units for most effective action so as to be mutually supporting: this is accomplished by scattering the forts to prevent the enemy from concentrating his fire, at the same time arranging them so that fire can be concentrated on him. (4) To protect well the flanks of the position and compel the enemy, if he attacks at all, to make a direct frontal attack. This is done by closing all unnecessary channels, by protecting the obstructions by means of rapid-firing guns and the operators by means of bombproofs, and at night by illuminating the obstructed field with search-lights. (5) To provide means for offensive returns against countermining operations, either by means of a swarm of torpedo-boats, or by batteries for operating movable torpedoes from the shore.

There are two systems of guns in use in coast artillery: the flat trajectory, high-power guns, designed to pierce the side armor of battle-ships, and the high angle pieces (howitzers or mortars) whose projectiles are designed to fall on the decks. Both are necessary, and each has its proper sphere of action, the former having by far the greater accuracy, and the latter attacking the battle-ship at its weakest point. In Europe howitzers are generally preferred; but the recent development of mortar fire in the United States service has proved the greater value of the latter. The calibre of the fort guns must be at least equal to that which the depth of water in the channel will enable the enemy to bring against the defenses and sufficient to pierce his armor at the outer mine field. The greatest thickness of Kruppized steel used in the latest battle-ships is about 16 inches at the belt, and to penetrate this at the required range will require a 12-inch gun. The average thickness of deck armor at present is about 3 inches of hardened nickel steel, and to penetrate this a high-angle gun (howitzer or mortar) 12 inches in calibre will be required. These are the maximum calibres required against battle-ships, but to prevent distant bombardment of cities, etc., there are larger rifles and for close ranges also an 8-inch rifle. Armored cruisers have from 5 to 6 inches of hardened nickel-steel armor, and to penetrate their armor within the mine field (where they first come seriously into play) will require a 5-inch or 6-inch rapid-fire gun. The smaller vessels have but little armor protection, but as they come into action at the outer mine field (about 3600 yards) the smaller calibre guns to fight them must have the necessary penetration at that range, consequently must be about 2.5 to 3 inches in calibre.

The number of guns of each calibre should be at least half of, and preferably equal to, those the enemy can bring to bear. The latter is determined by noting on the map the length of channel (within three miles of the fort considered) which the enemy's fleet can occupy, and allowing from five to ten ships to the mile. From the depth of channel the ships of the enemy which can go there can be determined, and from their armor and armament the kind and number of guns required. If the enemy's armament is not known, then in deep channels from 30 to 60 guns of 6-inch calibre and over must be allowed to the mile (Abbot).

The outer mine line is derived by the intersection of the curves representing the limit of armorpiercing ranges of the guns on either side of the entrance, so that these torpedoes are under the effective fire of all the guns in the harbor; the inner line is usually at the narrowest part of the

entrance.

The battle tactics of coast defense comprise defense against blockade, bombardment, and attack by sea.

DEFENSE AGAINST BLOCKADE.

The object of a blockade is the isolation of the port concerned in order to close all commercial communication by way of the sea, and presupposes the defeat of the enemy's fleet, which may also be shut up in the port. The observation of the movements of a daring enemy thus shut in is one of the most difficult problems which fleets have to encounter, and history shows that it is almost impossible. "For example, in 1759, the French fleet succeeded in breaking through the blockade of Dunkirk without being observed by the English fleet consisting of 66 ships." "In 1805 Nelson was in continuous observation of the harbor of Toulon. In spite of this fact the French fleet succeeded in running out, returning again because of injuries at sea, again leaving the harbor and joining the Spanish fleet, the combined fleets then sailing for the West Indies. Only after their return was Nelson enabled to seize them." The defender will naturally resist the blockade as long as possible and try to fit his fleet for active service again as promptly as he can. His first duty, then, is to keep the blockading fleet as far out as possible, and this duty will fall to the coast artillery, which must be constantly prepared, the guns ready for immediate action, the stations and range-finders continually manned, and the search-lights constantly at work. The plentiful use of electric light as a fighting agent is a passive factor, but one of very high value. His next duty is to inflict as much damage as possible on the blockading fleet, and this duty falls to the fleet stationed in the harbor, which must at all times be ready for action, and single torpedo-boats should be sent out under eover of darkness, to attempt the destruction of the enemy's ships. When the defeated fleet is ready for sea again the coast artillery will open a heavy fire on the enemy's ships, and, aided by their own artillery fire, the home fleet will endeavor to break through. This will naturally lead to a purely naval engagement, which need not be further considered here.

DEFENSE AGAINST BOMBARDMENT.

Bombardments aim chiefly at the destruction of the naval establishments of a fort, such as the arsenals, docks, magazines, and ships of the fleet lying in the harbor, but also secondarily at the destruction of cities and establishments other than those purely naval, in order to produce a depressing effect on the people. Bombardments are applicable only under special circumstances and not against every harbor; indeed, the latter must be a true roadstead. But even then the fortifications and armament must be either weak or obsolete. From this fact, and because of the limited supply of ammunition carried by ships, a bombardment will but rarely be justified. If it is attempted, however, the attacking fleet will set aside a small portion of its artillery to attack the coast artillery, reserving the greater part to attack the establishments lying within the harbor.

The defender will attempt to hold the open sea as long as possible with his fleet, but when driven in he will assemble his ships in rear of the outer obstructions, or at least attempt to hold that line with his torpedo-boats. The coast artillery will endeavor to keep the enemy as far as possible from the harbor. The object being to prevent, if possible, a bombardment of the harbor or city, all guns should take part, and when the enemy's fleet approaches the proper range, high-angle fire, with deck-piercing shell, will be used. The gunboats and coast defenders or monitors of the home fleet can materially assist the coast artillery by the fire of their guns, but they must be protected from the enemy's torpedo-boats by a. number of destroyers. As in case of blockade, the guns must be kept constantly manned and ready for action, and at night the search-lights must be constantly at work. Should the enemy be forced to retire, the home fleet must advance to the attack. See BOMBARDMENT.

DEFENSE AGAINST ATTACK BY SEA.

direct its efforts against a fortified harbor, or atIn attacking a hostile coast a fleet may either tempt to take possession of unfortified coast regions. The problem for the defense, therefore, naturally resolves itself into the defense of fortified places, and the defense of unfortified coast regions. The phases of the attack by sea in the first case are, in order, the removal of the outer obstructions, the reconnaissance, the artillery duel, the removal of the inner obstructions, the forcing of the entrance, and, finally, landings to obtain full possession of the forts. The phases of the defense will correspond.

Before endeavoring to ascertain the position of the guns of the defender, the attacking fleet will seek to destroy outer obstructions, in order opportunity should offer, to force the passage. to get possession of the outer bay, and, if the The torpedoes of the mine fields and the guns of the batteries on shore are complementary means The obstructions are a passive means, but only of defense, each inadequate without the other. become real obstacles when protected by the coast artillery; on the other hand, the latter alone, without the obstructions, cannot prevent the enemy from entering the harbor. The outer mine field is so important that there will be a serious struggle over it, for, once the attacking fleet passes over it, its further work is greatly simplified.

The defender, therefore, must be constantly on the alert, especially at night, when the searchlights are continually in use lighting up the foreground beyond the mines. All approaching ships. are fired upon by the artillery, and since the enemy will probably not attempt to remove the mines with any but his smaller vessels, such as torpedo-boats (since the outer mine field is placed intentionally in the field of greatest effect of the guns on shore, both vertical and horizontal), rapid-fire guns should be used, because these small vessels move rapidly, offer but a small target, and their work, by the time their purpose is known on shore, can be done promptly. Moreover, since the attack may be directed on several points of the mine field at the same time, it is best to assign the rapid-fire batteries to particular sectors of the mine field to insure prompt action on all the enemy's vessels. The torpedo-boats of the defense remain close up to the mine fields in order to fight the enemy's torpedo-boats while they are

COAST DEFENSE.

endeavoring to remove the mines. The counterattacking torpedo flotilla must be followed by one or two mine-laying ships, for repairing the damaged mine lines.

The attacker's object in reconnaissance is to obtain full and accurate knowledge of the location and power of the defender's guns of all calibres and kinds, the position of the torpedo batteries and mine observation stations, and finally to find out what new gun positions have been erected for the war. The defense, therefore, endeavors to veil all his batteries that cannot be readily seen from the sea, and to still further deceive the enemy he erects a number of small batteries. Batteries with disappearing carriages and mortar batteries have here a great tactical advantage, because they can be readily concealed. While the tieet is reconnoitring, therefore, beyond the outer mines, only such guns of the defense open fire as cannot be concealed, but as the ships come near the mines, and take up the formation in column, the other batteries open fire and with armor-piercing projectiles. Each battery is assigned to a different ship, on which it concentrates its fire, and which it follows until it is sunk or gets beyond armor-piercing range. The coast artillery is assisted in this work by the guns of the ships that may be in the harbor, these vessels moving inside the mine field on lines perpendicular to the enemy's line of advance, making the greatest possible use of their artillery, the torpedo-boats making counter-attacks when possible. The infantry garrison of the fortified place is posted on outpost along the shore, and prevents the enemy from landing reconnoitring parties, or fires on torpedo-boats sent along the shore to reconnoitre. In case the mine obstruction was removed by the enemy before his reconnaissance, the defender's larger vessels cannot take so advanced a position close up to the mine field, and as soon as the at tacker approaches the latter the defender must bring all his guns into action.

The object of the artillery attack is to silence all coast forts and batteries commanding the harbor entrance, to put out of action all guns mounted in them, and to destroy all positions flanking the obstructions. It is the preparation for the final assault. The main strength of the defense in this phase of the action will be the coast artillery, and since the enemy, because of his limited supply of ammunition, will probably endeavor to gain the upper hand as rapidly as possible, this artillery will require an energetic, decisive, and rapid service, and should be assisted by the artillery fire of the ships of the defense that may be in the harbor. The targets to be attacked are mainly the large, heavy battle-ships, of which the vital parts are protected by powerful armor. The latter must be destroyed to put the ship out of action, and this is a task set for the heavy guns. The conduct of the coast artillery must be systematic, and hence the command of fortified places is under a fortress commander, under whom are the district commanders, and these again control the group of battery commanders and the search-light stations. The heavier armor of a battle-ship is on her belt, extending above and below the water-line, while the deck is but slightly protected. The large calibre, flat-trajectory guns are used for piercing the heavy side armor, and with the new United States explosive D (or another of equal value, Maximite), and the delay-action fuse of the Ordnance

Department, the destructive effect is expected to be enormous. Howitzer or mortar shells are used for piercing deck armor; rapid-fire guns for firing on unprotected parts and clearing decks and tops.

The naval battle of Santiago clearly illustrated the value of a good artillery, and if such a magnificent action is possible from aboard ship, a far more favorable effect is to be expected from the land. But this battle also shows how dangerous it is to neglect all preparations on the part of the coast artillery, and the Spanish coast artillery must bear a large portion of the blame for the sacrifice of Cervera's fleet. Special attention must be paid to the equipment of the observation stations of the district artillery commanders. Good telescopes and photographs and plans of the enemy's ships must be on hand for immediate use, to enable them to recognize the different ships, and in the group and battery commanders' stations there must be more detailed plans of the ships to determine the projectiles to be used at various ranges. Works are now published giving, in silhouette, the appearance (to the naked eye, at a particular distance) of every important war-ship.

The inner obstructions consist of lines of mines, sea barricades, and occasionally also of a submarine dike. The decisive engagement for the possession of the harbor will be fought at this barrier, for which reason it is protected by numerous rapid-fire and torpedo batteries. The reconnaissance of the inner obstructions, and even their partial removal, may be attempted by the enemy during the artillery duel, hence the defender must make constant use of his search-lights to detect such a move. The assailant will first attempt to destroy the inner obstructions by means of torpedo-boats, then he will try to break them up by artillery fire, and finally he may attempt to land detachments at night to blow them up, or send a drifting mine-destroyer against them. The inner mines are usually within the effective armorpiercing range of the heavy guns, as well as under the fire of the rapid-fire batteries; the former act against the armored ships, the latter against the small and fast torpedo-boats or unarmored vessels.

The forcing of the entrance is the closing act of the assailant's undertaking, and its object is the final occupation of the disputed harbor. At the head of the final assault are torpedo-boats which, acting as a patrol, make a final attempt to break through the obstructions. These, as well as the torpedo flotilla following them, should be greeted with a hail of projectiles from the rapid-fire guns of the shore batteries. All other coast guns and howitzers should be directed against the battle-ships of the attacking fleet, and should fire especially at the leading ship. As the attacking vessels enter the harbor the fire of the coast guns is concentrated more and more against the vessels following. This artillery battle is continued until each fort in succession is taken by the enemy. The home fleet inclosed in the harbor should now attempt to break through the lines at all hazards, and this can best be done at night. Unfortified coast regions are subjected to attack by the enemy's fleet, the purpose being either to support the operations of a land army, er to attack a fortified harbor from the land side.

Military history proves that it is by no means easy to capture a well-defended harbor by the