SHIPPING-MASTER

ter who built it, and must have it surveyed. If the ship or any interest therein is sold, or if it is altered in form or burden, a new registry is required. If the vessel is not to be engaged in foreign commerce, but in the coasting trade or in fishing, instead of being registered it must be enrolled, if of 20 tons and upward, or if of less than 20 tons it must be licensed. (U. S. Rev. Stat., §§ 4311-4390.) Under this legislation U. S. ships have a virtual monopoly of the coasting

trade.

4462.

Inspection of Steam-vessels.-The owners of registered or enrolled steam-vessels navigating the public waters of the U. S. are required to have them inspected from time to time, and to obtain a certificate that they are suitable for the service in which they are employed. U. S. Rev. Stat., § 4399Many of the rules relating to this branch of the law are set forth in other articles and need not be repeated here. See ADMIRALTY, AVERAGE, BILL OF LADING, CARRIERS, COMMON; CHARTER-PARTY, Demurrage, Freight, JETTISON, LIEN (Maritime Liens); MARINE INSURANCE, PILOT, ROAD, LAW OF THE; SALVAGE, SEAMEN, and STOPPAGE IN TRANSITU.

more powerful fleet was in like manner transported to Lake Garda, and accomplished the relief of Brescia. Thirteen years later, at the siege of Constantinople in 1453, the mouth of the Golden Horn being closed to their ships by heavy chains, the Turks moved a large fleet from the Bosphorus into the Golden Horn behind the chains in a single night, over rudely constructed timberways 5 miles long, thereby almost doubling the length of line which the besieged had to defend, and largely contributing to the city's fall and the consequent end of the Greek empire. In 1718 Swedenborg conveyed a shallop, two galleys, and four large boats 5 leagues over mountains and valleys from Stromstad, Sweden. Application of Railways to Navigation.-The first application of railways to navigation occurred in providing substitutes for locks on canals and in one notable instance for the canal itself. The Bude Canal in Cornwall, England, between Bude and Launceston, has been in use since 1826. At Hobbacote Downs the canal-boats, which are furnished with Small iron wheels, ascend to the uplands by an inclined plane 900 feet long provided with two lines of rails terminating at each end in the canals. There are seven of these inclined planes on the Bude Canal.

The Morris and Essex Canal in New Jersey is operated with inclined planes connecting different levels. Before the Pennsylvania Railroad was built a portage rail

The literature on this subject is very extensive. Among the most important treatises are Abbott, Law of Merchant Ships; Dixon, Law of Shipping; Maude and Pollock, Law of Merchant Shipping; Parsons, Law of Shipping; Reeves, History of the Law of Shipping and Navi-way 30 miles long was in operation across the Alleghanies gation; Wynkoop, Vessels and Voyages.

Shipping-master: See SEAMAN.

FRANCIS M. BURDICK.

Ship-railways: railways for the transportation of ships overland between separated bodies of navigable water. The connection between the water and land-transportation is effected by lowering the ends of the railway-tracks into the water to such a depth that the ship floats on and off a carriage or cradle. This is done by means of hydraulic liftingdocks, inclined planes, or any of the other methods in common use for raising ships out of the water for repairs. Method of Operating a Ship-railway.-The cradle, having on its deck a line of supports along the center to receive and sustain the keel, with other supports for the bilges arranged on each side, is lowered on the rails into the water. The vessel is then brought into position and the cradle is raised to a bearing along the keel, and the bilge-supports are adjusted to place, after which the cradle and vessel are lifted out of the water to the level of the tracks on shore. The motive power is then applied, and the ship is taken across the railway line to the other harbor and lowered into the water by the means employed in raising it.

Early Methods of Overland Transportation.-Transportation by means of portage is the most ancient form of artificial navigation. The first ship-road recorded is one that was used through centuries, the Diolcus of Corinth, which existed at the time of Aristophanes, 400 B. C., and which is said to have been in operation 300 years. It connected Schænus to Port Lechæum, and its remains can still be seen there. It is thus described in the Lexicon of Cornelius Schrevelius: "A track on the Corinthian isthmus where ships were hauled out of the Ionian into the Egean Sea." The ships carried are said to have been about 150 feet long and 18 feet wide, with a draught of 84 feet. It is very probable that before the Diolcus was built the practice of transporting ships overland was long in use, for the ability to handle such ships as those mentioned must have had a long and slow development, with the limited knowledge and power at the service of the engineers of those days. It is said that this method of suip transport was employed by the Greek admiral Nicetas Oory fas in the year 831 to attack the Arabian corsairs who were then devastating the coasts of the Peloponnesus.

between Johnstown and Hollidaysburg, upon which canalboats were carried in sections from one canal to another.

In 1860 Sir James Brunlees and E. C. Webb proposed to the Emperor Napoleon III. a ship-railway across the Isthmus of Suez in lieu of the ship-canal. Marshal Vaillant, Minister of War, referred the matter to M. de Lesseps, who rejected the idea. It was proposed to make the railway level throughout, have ten rails in its track, and to use there for the first time the hydraulic lift invented by Edwin Clark, and since so successful at the Victoria Docks and elsewhere. The speed was to be 20 miles per hour; that on the ship-canal, for steam-vessels, is 5 miles per hour, a difference in favor of the ship-railway which, as soon as its practicability is demonstrated elsewhere by everyday use, may cause it to supersede its one-time successful rival. Messrs. Brunlees and Webb also in 1872 prepared plans for a shiprailway which the republic of Honduras proposed to build across its territory from Puerto Caballos to the Bay of Fonseca. It was to carry vessels of 1,200 tons, and doubtless would have been successful had the republic found the money to carry out the work. Another plan of great interest for a ship-railway was that of Sir John Fowler for passing the cataracts of the Nile.

The Chignecto Railway.-In 1875 H. G. C. Ketchum, C. E., of Fredericton, New Brunswick, proposed a ship-railway as a substitute for the Baie Verte Canal across the Isthmus of Chignecto, to connect the navigation of the Gulf of St. Lawrence and that of the Bay of Fundy. From the report in 1783 of Col. Robert Morse, chief of the Royal Engineers, recommending the construction of the Baie Verte Canal as an important necessity of commerce, the question of where and how it should be built was never allowed to drop. In 1822 the first actual survey for a canal was made by the government of New Brunswick, and from that time until Mr. Ketchum's survey in 1881 of the ship-railway line there was no possible canal route that had not been gone over and reported on, so great was the interest of Government and individuals in the question. The ability and perseverance of Mr. Ketchum, and the superiority of a ship-railway for the purpose intended, finally carried the day. The proposal to form a company to build a ship-railway was accepted by the Dominion Government, and an annual subsidy of $170,602 was granted for twenty years. The company was not to call on the Government for any portion of the subsidy In 1438 the Venetians transported under the direction of except what might be necessary to make up the net earnNicolo Sorbolo, a civil engineer of Venice, a fleet of thirty-ings of 7 per cent. on the authorized capital of $5,500,000, three vessels overland from the river Adige to Lake Garda, and it agreed to pay over to the Government half of the a distance of 90 miles, the motive power on the plains being surplus profit beyond the 7 per cent. until the whole of the oxen and on the mountains windlasses worked by men. The subsidy which might have been paid to the company should largest ships of the fleet averaged 148 feet in length, 40 feet be repaid. beam, with a displacement of 300 tons, and were armed with the ponderous stone-throwing artillery of the period, and laden with large stores of cross-bows, arrows, lances, and all the usual munitions of war in vogue.

The object of the expedition was to relieve the city of Brescia, at the time besieged by the Milanese. This was accomplished in a measure, but the Milanese captured and burned the fleet. Early in the spring of 1440 a larger and

In 1888, under Sir John Fowler, Sir Benjamin Baker, and H. G. C. Ketchum as engineers, the construction of the Chignecto ship-railway was begun. It is 17 miles long, and on a straight line from end to end, running through a country moderately rolling, with only one watercourse to cross, and generally favorable to the rectilinear location and f per cent. maximum grade adopted.

Fig. 1 shows a vessel as it will look on the lifting-dock

ready for transportation. The vessel, resting on blocks along its keel and bilges, is supported on platform-cars 38 feet wide, carried on 240 wheels, arranged in four lines to run on two tracks of standard gauge, 18 feet apart between

FIG. 1.

centers. The gridiron on which the ship and cradle move up and down in the lifting-dock is like the deck of a bridge with floor-beams arranged in pairs, slightly separated to admit the hydraulic presses between them, and are connected in the usual way by track-stringers under the rails. The hydraulic presses are 25 inches in diameter and twenty in number, and are designed to lift a vessel carrying 1,000 tons of cargo, together with the cradle and gridiron, a total weight in all of 2,500 tons. They are placed 21 feet apart longitudinally and 64 feet transversely, and have a maximum stroke of 40 feet. The cross-heads on the inner cylinders or rams are attached to the floor-beams with eye-bars.

of the gate proper is 17 feet lower, or 13 feet below high water spring tide, and retains a minimum depth of 32 feet in the basin. The lifting-dock at the inner end of the basin is 270 feet long. Vessels will be able to enter or leave during the

high stages of the tide, while the excellent anchorage off shore, and the large storage capacity of the basin, insure a continuity of traffic uninterrupted by the fluctuations of the bay. This pioneer ship-railway is (1895) more than three fourths finished. Awaiting the completion of this great work are many others that are projected, and whose construction will doubtless quickly follow.

The Hurontario Railway.-This is to connect Georgian Bay with Lake Ontario at Toronto. It is to be 66 miles long, probably in one straight line; the maximum grades going south (the direction of heaviest traffic), 8 feet per mile; going north, 22 feet per mile; its track will consist of six rails, and the estimated cost is $15,500,000. The available water-power along its line is over 100,000 horse-power, from which electricity for doing all the work of operating the railway will be generated. The saving in distance over the route around by way of Detroit is about 300 miles, while the country through which it is to run favors facility and permanence of construction. Columbia River Railway.- A boat-railway along the Dalles of the Columbia river, U. S., between Three Mile Rapids and Celila, is under way, Congress in Aug., 1894, having appropriated $100,000 for the preliminary work. The novel feature of this work is the proposed use of one-degree curves on the railway. The track would be similar to the Chignecto ship-railway, and the general features are also alike with some variation in details to suit the flat-boat traffic for which it is designed.

The Tehuantepec Railway.-This was first proposed by Capt. James B. Eads in 1879, and with characteristic en

tion, he pushed through all the stages of preliminary surveys, detailed plans, congressional inquiries, procurement of concessions from Mexico, and some actual construction at a cost of more than half a million dollars. A table of the distances the railway would save is unnecessary, for it is plain that lengths and breadths of continents are involved. With the opening of the Suez canal, one of the two great barriers to interoceanic navigation was removed. The completion of the Tehuantepec ship-railway would remove the other.

When a vessel is to be lifted the gridiron, with a cradle on its tracks, is lowered, and the vessel is hauled into posi-ergy, in a few years, in the face of almost universal opposition with hydraulic capstans. Water is then forced into the presses until the keel-blocks are brought to a bearing; next the bilge-blocks are drawn into place and the pumps are again started, raising the gridiron in less than ten minutes to a position where its tracks are slightly above those of the railway. A connected system of heavy iron chocks, supported by the masonry, is then moved under the ends of the girders by hydraulic power, the gridiron is lowered to a bearing on them, and its tracks are connected with those of the railway. Two locomotives will haul the ship across the isthmus in less than two hours, and the lifting-dock at the other end by a reverse operation quickly replaces it in the water.

The track is composed of rails weighing 110 lb. per yard, laid on very heavy ties, some of which extend under all four rails. It is stoneballasted, on the most solid cuttings and embankments, and is characterized by smoothness and rigidity.

A novel feature is the way in which the difficulties arising from the immense tides of the Bay of Fundy are overcome. A basin 500 feet long and 300 feet wide is constructed at the south end. The en

trance-gates and sea

Tehuantepec was selected as the proper location because of its greater proximity to the U. S., its superior advantages

FIG. 2.

walls are of heavy masonry, the top being at the common in distance and time to the main lines of commerce, its level of the top of the lifting-dock and railway. The top more healthful climate, the easy grades that are practicable

490

SHIP'S MAGNETISM

SHIPS OF WAR

pass C. A. Schott was enabled to trace out with chalk on the | due to the joint disturbing effect of the vertical components iron gun-turret (sides 11 inches thick) of an ironclad vessel its of permanent and of induced magnetism. magnetic equator, and found its plane inclined to the hori- The values of the coefficients A, B, C, D, E, are found dizon at an angle of nearly 90° dip; after revolving the tur-rectly from observations, the deviation of the compass being ret 180°, the line of no polarity again was traced out, when observed with the ship heading in a number of equidistant the plane, passing through the intermediate horizontal po- points around the horizon, usually either 32, 16, or 8. If sition, gradually approached its former place after a lapse the deviation is observed on four cardinal compass-points, of about twelve hours; it probably takes weeks before the D remains indeterminate; if on four quadrantal compassfixed position is reached, depending on the action of the points, E remains indeterminate. These observations are iron. Inside such turrets the magnetic intensity is very made by swinging the ship (or allowing it to swing by the much weakened, but 12 per cent. was found to be left in tide), and noting for the several headings the bearing of a the above case. The reader is referred to Sir George B. distant object, or by reciprocal bearings if the locality be Airy's Treatise on Magnetism (London, 1870) and to the confined, or when at sea by azimuths of the sun, the local Admiralty's Manual for the Deviations of the Compass, by time and latitude being known. The deviations being deCapt. F. J. Evans, R. N., and Archibald Smith (London). termined for a number of points, they may be plotted on This manual is the standard work on the subject of the de- what is known as Napier's diagram, and graphically interviation of the compass. polated by drawing a curve with a free hand through the several fixed positions. The deviations for any compass course will then become known. They may also be tabulated. If we deduce numerically the coefficients A, B, C, D, E, we can compute directly the values of 8 for plotting or tabulation. În either case we know the correct magnetic course corresponding to the disturbed or compass course, as well as the reverse of the compass course belonging to any correct magnetic course. It has been remarked that inside iron turrets the magnetic intensity is greatly diminished; the same is the case with nearly all iron ships, the directive force of the needle being diminished. The relative horizontal force is found by means of the number of oscillations in a given time of a small needle, and the proportion of the disturbed to the undisturbed horizontal force, usually called a, is determined from oscillations in four equidistant azimuths. It is usually less than 1, and is closely connected with the coefficient D, as may be surmised from the fact that a is due to the effect of the horizontal induction of soft iron. D and λ are nearly constant. A knowledge of the value of a is of importance; by its assistance the values of B and C may be found without swinging the ship from observations of and a on one course; similarly, observing on two courses, we may determine B, C, D and A. The value of λ is further needed in the computation of the heeling tan .i. cos' for

The earth's magnetic force has been represented by three component forces, to the ship's head, to the starboard side, and to the keel respectively; similarly, the components of the combined total magnetic force of earth and ship are in these directions; their respective differences or components of disturbance can be expressed by linear equations possessing each a constant and three coefficients, which are to be determined by experiment for each ship and position of compass, and must be numerically worked out by application of the method of least squares.

The general character of the deviation in wood-built sailing ships, with compass as usual on the quarter-deck and over the middle fore-and-aft line of the ship, is found as follows: No deviation when heading (magnetically) N. or S.; greatest deviation when heading (magnetically) E. or W.; deviation easterly when head in eastern semicircle, and westerly when head in western semicircle. In steam-vessels, with the compass aft, these directions of no and maximum deviation will often be found displaced by several degrees, yet preserving their general symmetrical character. In the southern (magnetic) hemisphere the deviations are reversed, though for steam-vessels they may be only partially changed. In ironbuilt ships an individual character has to be recognized. The points of no deviation are shifted from the N. and S. points, and lie nearly in the direction (by compass) of the ship's head and keel while building; they may not be oppo

site to each other, nor be removed exactly at right angles

==

error, which is expressed—(D +

a heel of the vessel of + degrees to the starboard. Here is the ratio of the disturbed vertical force at the compass to the earth's vertical force; it is found by means of oscillations of the dipping-needle in the plane of the magCnetic prime vertical; changes with a change in the geographical position; e is the magnetic dip. It is therefore not actually necessary to heel the ship in order to determine the heeling deviation. It should be added to the general deviation table.

from the point of maximum deviation. In general, the de-
viation is easterly when the part of the ship which was S. in
building is E. of the compass; westerly when W. The de-
viation described above is technically known as the semi-
circular_deviation, and may be expressed by B sin
cos. In the general deviation formula 8=A+B sin
C cos + D sin 25+ E cos 25, the angle being the azi-
muth or the compass-bearing of the ship's head reckoned
from the disturbed magnetic meridian positive to the east-
ward; it is a constant, generally small,+ if easterly devia-
tion is in excess. + B is approximately the deviation at E.,
and Cat N.; in the last terms of the harmonic function
involving 25, and which are technically known as the quad-
rantal deviation, + D is the mean deviation approximately
at N. E. and S. W.; the coefficient E is generally small or
zero; the deviation & is reckoned + when the N. end of the
needle is drawn to the E.; and the above empirical expres-
sion applies, provided the deviation on any course does not
much exceed 20°, or about two points, in which latter case
the formula becomes more complicated. The correct mag-
netic course will be +8. The semicircular deviation
rarely exceeds 10° in wood-built vessels, but in iron-built
ones may reach double and treble this amount. The quad-
rantal deviation seldom exceeds 1° or 2° in wood-built ships,
but in iron-built ones may reach three or four times this
amount. The semicircular deviation is principally due to
the effect of permanent or sub-permanent magnetism. The
quadrantal deviation, which undergoes no change with a
change in the ship's place, is mainly due to the effect of in-
duced magnetism.

The heeling error in wood-built ships is not appreciable, but in iron-built ones it may be serious; generally, the error vanishes with the ship's head at or near E. or W., and attains a maximum value with headings at or near N. or S. The sign of the error changes with a change from the northern (magnetic) to the southern hemisphere. In the northern (magnetic) hemisphere, with the compass above the upper deck, the majority of iron ships have the N. end of their compass-needle drawn to windward, and in the southern hemisphere to the leeward. The heeling error is

The mechanical correction of the deviation of the compass is properly resorted to in case no suitable position for the standard compass can be found where the deviations are comparatively small; in ships built head S. (northern hemisphere), and intended for navigation in northern magnetic dips, the compass should be placed as far forward as practicable. It may also be elevated 3 or 4 yards above deck. The semicircular deviation may be corrected mechanically, either by means of two magnets or by one magnet; the quadrantal deviation may be corrected by a mass of soft iron placed near the level of the compass; the same may be effected by the mutual action of two compasses placed side by side; the heeling deviation may be corrected by the application of a vertical magnet. In mechanically corrected compasses there is always some danger that, with change of geographical position, loss of magnetism of magnets, and change in the sub-permanent magnetism of the hull, deviation may reappear, though the disturbing force may have been completely neutralized in one place and at one time. It is therefore never to be trusted, and, as a rule, deviation tables should be formed whether mechanical corrections have been applied or not.

An excellent collection of important memoirs, entitled A Series of Papers from the Transactions of Foreign Societies by Poisson, G. B. Airy, A. Smith, F. J. Evans, W. W. Rundell, with other papers and documents, has been published by the British Admiralty. Revised by FRANK H. BIGELOW. Ship's Papers: See the Appendix.

Ships of War: vessels built and armed for offensive or defensive purposes. Modern war-ships include the fol

The

lowing types: armored vessels for the line of battle and for In view of these successful results, the French detercoast service, armored cruisers, rams, protected cruisers, un- mined to build ships which should combine with their proarmored cruisers and auxiliaries, gun-vessels, gunboats, tor-tective armor satisfactory seagoing qualities, and in Mar., pedo-vessels, torpedo-catchers, torpedo-boats, and various 1858, the first ironclad frigate, La Gloire, was begun at Touvessels for harbor service. It is the endeavor to give in this lon. The construction of two other wooden armored frigarticle a brief historical sketch of modern naval construc- ates the Invincible and the Normandie, of the same type as tion in Great Britain, France, and the U. S., which, until the Gloire-and the Couronne, an iron vessel, was ordered. the later activity of the Italian authorities, have alone origi- The latter ship differed from the others not only in the nated types of war-vessels; this to be followed by descrip- materials employed, but in the strength of the deck, which tions of the more important typical war-ships of the vari- afforded protection against the projectiles then in use. ous classes, which may serve to render more intelligible the Couronne was especially constructed with a view of estabtabular statement of the ironclad navies of the world. lishing comparison between wooden vessels and those of Incentives to the Application of Armor.-Since about the iron. The four frigates were completely armored above middle of the nineteenth century a revolution has been the water-line with 5-inch plates resting on a 26-inch wood brought about in naval construction, and new systems have backing. The armament consisted of thirty-six 5-ton guns been adopted through the influence of the following agents: mounted on a single battery, extending the whole length of (1) The application of steam, strictly the screw-propeller; the ship, 6 ft. 3 in. above the water-line. (2) shell-firing and the increased power of artillery; (3) the use of armor; (4) the submarine torpedo. Up to the time that the advantages of the screw were established to the satisfaction of admiralty boards, steam-vessels were regarded valuable merely as auxiliaries, owing to the vulnerability of paddles and machinery, the limited scope of the battery, the enormous coal-consumption of their engines, and the difficulty in making paddle-wheel steamers good sailing vessels. The U. S. steamer Princeton (1842-43) was the first screw war-steamer. She was designed by Ericsson, and her construction and success were mainly due to the efforts of Capt. Robert F. Stockton, U. S. navy. Great naval powers are reluctant to begin changes that involve costly reconstruction; this, with the conservatism regarding any new system, was the reason of the otherwise inconceivable reluctance of the British to take up the project of a screw-navy. When the French built the line-of-battle screw-ship Napoleon (1850), the British took alarm and began reconstruction with vigor; and the renovation of their navy by the application of the screw was well advanced in 1859, when the French launched the ironclad wooden frigate La Gloire. Then began the decline of unarmored battle-ships.

The principal incentive to the application of armor was the destruction anticipated from shell-fire. It was not until 1854 that naval batteries consisted entirely of shell-guns, the magazines being filled with loaded shells entirely fused. Admiral Dahlgren carried the application of this missile to great perfection in the U. S. frigates of 1854. The Merrimac, one of these, visited Europe in 1856, startling naval administrations by the enormous shell-power of her battery. The swift destruction of the Turkish fleet at Sinope by the shells of the Russian ships during the war in the Crimea (1853) had much to do with hurrying forward the application of armor; the destruction of the Congress and the Cumberland during the civil war in the U. S., and the Monitor and the Merrimac engagement, gave it fresh stimulus.

66

Early Forms of Armored Ships.-The first definite proposal for building an ironclad was made in 1841 by Robert L. Stevens, of Hoboken, N. J.; armor, it is stated, was suggested by his father, John Stevens, in 1812. An act approved Apr. 12, 1842, authorized the Secretary of the Navy to enter into a contract with Stevens for the construction of a war-steamer for harbor defense, shot and shell proof, to be built principally of iron." The contract was made Feb. 10, 1843, and altered Nov. 14, 1844, increasing the dimensions so as to make them as follows: Length, 415 feet; beam, 48 feet; depth, 33 ft. 6 in.; protection, 64 inches of iron; horse-power intended, 8,624. Work was begun in 1854; and when the vessel was about half completed, the Government refused further appropriations.

It was the initiative taken by the Emperor Napoleon III. which brought about a complete revolution in modern naval construction of war, as the first ironclads used in battle were the French batteries Dévastation, Lave, and Tonnante, begun for service in the Crimea in Sept., 1854, two months after the keel of the Stevens battery was laid at Hoboken. They were all of the same dimensions-namely: Length, 171 ft. 9 in.; beam, 43 ft. 1 in.; draught, 8 ft. 8 in.; hulls, of wood; armor, 433 inches thick; armament, 16 guns of French "50," corresponding to 68-pounder, carried 2 ft. 11 in. above water-line. They were about 1,600 tons displacement, with speed about 4 knots an hour. They formed part of the fleet, carrying 1,500 guns, which destroyed Fort❘ Kinburn, an inferior barbette work. The ironclads engaged at about 1,000 yards, at which range they were proof against 32-pound shot with 10-pound charges. The British adopted the design and built five, but they were never in action.

Great Britain at last decided to follow in building armored ships. The Warrior was ordered in June, 1859, a few months before the completion of the Gloire. The Warrior and her counterpart, the Black Prince, were one-half greater displacement than the Gloire, and 132 feet greater length; they were built entirely of iron and armored with 4inch iron plates over a length of 218 feet out of a total length of 380 feet. Their speed was 14 knots, compared with 128 for the Gloire. The wise choice of the material of construction leaves them serviceable vessels to-day, while the French ships were some years since stricken from the list. The Defense and the Resistance, of 6,150 tons displacement, with similar disposition of armor, were begun at the same time. In 1861, following upon the four ships just mentioned, Great Britain undertook the construction of not less than eleven ironclads, representing four different types the Achilles, 9,820 tons displacement, armored along the whole length with 4-inch plates, then the Minotaur, the Northumberland, and the Agincourt, of 10,700 tons displacement, similar to the Achilles, except that the armor was 5 inches thick amidships, tapering to 3 inches at the extremities. The vessels of the fourth type, the Hector and the Valiant, have proved more serviceable than the others, being smaller, more manageable, and much more economical; they were armored throughout the whole length with 4-inch plates, the protection being only above the waterline at the bow and stern. The Magenta and the Solferino, laid down two years after the Gloire, formed part of the first group of French ironclads. The second group consisted of ten vessels of the Provence or Flandre class. The displacement was slightly augmented, but the protection was increased to 6 inches of armor.

Up to 1855 the vessels built for the U. S. navy were the best possible specimens of their class; among the early steamers, the Powhatan and the Susquehanna, at the time they were launched, in 1850, were the most efficient naval vessels afloat. The screw frigates, built in 1855, were regarded all the world over as the model men-of-war of the period. Of these, the largest was the Niagara. The other five-the Roanoke, the Colorado, the Merrimac, the Minnesota, and the Wabash-were vessels of about 5,000 tons, and carried a powerful battery of shell-guns. The twelve screw-vessels were of two classes, built in 1858, the first, of about 3,000 tons, including the corvettes Lancaster, Hartford, Richmond, Brooklyn, and Pensacola; the second class, small sloops. These were all admirable vessels, but they were no advance upon the type of the Wabash class. At the beginning of the civil war, of the ninety ships on the naval register fifty were sailing vessels, and only twenty-four of the forty others were serviceable steamers. The construction of iron or armored vessels had not been begun, and sail-power had been only partly replaced by steampower. At the outbreak of the war a special naval board was appointed to determine upon types of ironclads to be built for immediate service. The three ships ordered on the recommendation of the board were the broadside vessels Galena and New Ironsides, and the Monitor. The first vessel was armored with bars, of 24 inches total thickness, put on in a very complicated manner, which proved so deficient that the vessel failed in the first test under fire, in the James river, in an action from which the Monitor came out unharmed. The New Ironsides was a casemated ironclad wooden frigate with unarmored ends, except that the waterline belt was complete all around. Her armor consisted of 44-inch solid plates backed by 21 inches of oak, the whole inclined throughout the casemate at an angle of 30° from the vertical. Her battery consisted of fourteen 11-inch