been decisive that the chief reliance of maritime nations must be in iron-armored ships. - But what shall be said of the revolutionary work of steam? One sentence will tell the story as plainly as a quarto volume. The screw-propeller has changed, at once and forever, the entire motive-power of war-vessels. We attribute this revolution to the "screw-propeller." For many years after the introduction and wide-spread use of steam in commercial craft, warships did not use it. The reason was twofold; first, because of the disarrangement which the huge paddle-wheels must have made with the battery and also with the use of sails; and secondly, because of the fatal exposure of machinery to an enemy's shot, which rendered the paddle-wheel vessel liable to utter helplessness from a single discharge. The honor of inaugurating the new era was reserved for Captain John Ericsson, and through him for America. The propeller he introduced is, to the present day, with some slight alterations which do not materially affect its efficiency, the one universally employed. Attempts previous to his seem to have been little. more than a repetition of the Archimedean experiment of revolving a submerged worm, or helix, attached to a vessel. A complete master of the physical laws involved in the action of oblique surfaces moving in water, and adding thereto high scientific and professional attainments and great mechanical skill, Ericsson was able to plan his propeller, and all its attachments of steam-engines, with perfect accuracy. The entire contrivance worked precisely as predicted, and with no alteration, — all as laid down by him on his drawing-board. We are not, accordingly, to look for any radical improvement on the propeller in future. The United States steamer Princeton was the first war-propeller ever built. And so admirably well was every part of her machinery planned and constructed, that, when it had worn out one hull in service, a new hull was provided. The Princeton was launched in April, 1842, a monument of engineering skill. Not only was she the first war-propeller ever built, and the one on which, with slight modifications in de For proof of this point, see Bourne on Screw Propellers; also, Encycl. Britannica, Vol. XX. p. 639. tails, the vast screw navies of the world have been constructed, but her engine was the also first direct-acting engine, that is, one in which the engine seizes directly hold of the shaft, without the intervention of gearing. She was, finally, the first war-vessel which had her entire steam-machinery placed below the water-line, out of the reach of shot. The Greeks and Romans understood the importance of keeping the motive-power of their galleys well protected. They interposed great casemates, so to speak, for the protection of the oarsmen. No manoeuvring in naval combats, from those early days to ours, was comparable to that which one reads of in the seafights from Salamis to Actium. Ships never were handled so quickly in actual combat under sails as they were under oars; but, above all, the motive-power was never so well protected. After the lapse of so many centuries, we again equal and surpass the ancients in both particulars. The ingenious contrivance of faking the chain-cable along the sides of the ship, in combat, at Forts Jackson and St. Philip, and again more famously on the Kearsarge, is well known. The Princeton would have had no need of such protection, for her steam-machinery was all below the water line. A departure from this principle, in the case of all our wooden screw ships built before and during the war, suggests the painful possibility of utterly ruining their availability by a single well-directed shot. It was with inconceivable reluctance that the British Admiralty took up the project of a screw navy. They had rejected Ericsson's invention in 1837, when he had not only offered them his propeller at the outset, but had demonstrated its value by trials with it upon the Thames. The eagerness with which the United States first seized the new instrument, and, more particularly, the alacrity with which France afterwards adopted it, actually forced the English government into building screw ships. The renovation of the entire British Navy, and the substitution of steam for sails, was at length completed, at great expense, in 1859. While we were not quite as slow as the English in this matter, our Navy Department (as it now and then will) in at least one matter vied with them in dulness; for after the propeller was an established success, the British were building sailing frigates, and we, lumbering paddle-wheel frigates. Vast numbers of screw steamers now figure on the British Naval Register. Nearly all of them, however, nearly all, at least, of large size, with the notable exception, of the Mersey class of frigates, built expressly to compete with our frigates of the year 1854, after the visit of the Merrimack to Southampton, are sailing vessels, altered to receive the propeller. In some cases these were lengthened, in others the sterns were reconstructed; in others, both alterations were made. Their wood was almost indestructible, being, in the chief parts of the ship, either teak or live-oak; and hence, when the propeller was put in, they were, for strength and soundness, quite as good as new. Still, the iron-clad now takes the place of these old-fashioned, heavy wooden vessels designed for defence. The work now devolving on wooden ships is different. Fighting each other, assailing commerce, and transport service are the duties to which the wooden fleets of the world are assigned; and even for depredations on commerce and for transport service they are now, or soon will be, behind the times. So, as we have seen, does steam sweep away fleets and systems of warfare, and render the accumulated naval power of nations of little effect. To show its enormous influence, it will be sufficient to instance a single country, England. She ruled the seas of yore by her trained seamen and by her skill in naval manœuvre. Her models were not better than those of rival nations. Indeed, her ships were not as good as those of France or Holland, throughout the eighteenth century. But her seamen were the best in the world.* At one fell swoop this prestige is gone, since mechanism now performs the functions which once required men. Astonishing as this fact is, and it is a fact already admitted by British writers, it is not less so than one other, which shows how strategic position is affected by this revolution in naval warfare. Of old, Britain, safe in her "salt-water girdle," and surrounding herself with a cordon of well-manned navies in the Channel, in the Irish Sea, in the North Sea, and in the Atlantic, laughed at attack. The reminder of Cymbeline's Queen to her royal spouse was always comforting enough to the descendants of their subjects: * See Alison, Vol. II., on the battle of Trafalgar. "Remember, sir, my liege, The kings your ancestors, together with The natural bravery of your isle; which stands As Neptune's park, ribbed and paled in With rocks unscalable, and roaring waters; With sands that will not bear your enemies' boats, This notion of the availability of the Channel as a line of defence has always been a favorite one with Englishmen, from the days of the Druids to the days of the Guelphs. Now, however, it has been rudely shocked, and perhaps entirely driven out. "The introduction of steam as a propelling power of ships," says a good authority, "has been regarded by some persons as wholly revolutionizing all previous warlike theories. The Duke of Wellington adopted this idea; but Lord Palmerston, above all others, has maintained that the new system has almost annihilated the Channel as a line of defence. . . . . The Report of the Defence Commission adopted, though with less positiveness, the Premier's idea."* We would gladly pause upon some of the points already suggested, as well as upon matters collateral. But we are fully aware that all the popular interest now attaching to the "mechanics of naval warfare" concentrates upon the great ironclad question. At this moment this discussion is pushed with extraordinary vigor in England and France. And, indeed, it well may be, for it is of most momentous importance to the welfare of those countries. In this country, having chosen our system long since, and being wedded to it, finding it true in the hour of exigency, for us the period of harassing uncertainty is past; but in England no scientific question in the whole realm of warfare gets so much and so earnest discussion as this. Within a twelvemonth, probably more than a thousand different articles, of one sort or another, on this subject, have appeared in public there, from the laborious volume to the newspaper paragraph. To this subject, therefore, we will devote as much space as possible. North British Review, August, 1863. When this startling theory of the loss of the Channel as a line of defence was first propounded, Sir Robert Peel, as in duty bound, rigorously attacked it. But Lord Palmerston, in 1860, declares Sir Robert Peel to have originated and maintained it. Armored vessels may be classified under two general heads; namely, broadside iron-clads, and monitors, or turreted ironclads. The broadside iron-clad is a vessel of the ordinary form, distributing her guns along both sides of the ship, and having a cuirass of iron secured to her sides. The monitor is a vessel in which the battery, instead of being distributed, is concentrated in pivot guns, protected with a revolving shield or turret of iron, so arranged that, by turning it, the guns can be aimed in any direction. These, of course, are not definitions of the rival systems, but only partial descriptions of some of their most palpable differences. We shall see the other points of distinction in proceeding. The leading maritime nations of the globe now intrust their naval prowess to iron-clads built on one or other of these two systems. France, England, Turkey, and Italy have adopted the broadside system; the United States, Russia, and Sweden, the turret system. To the turreted iron-clads alone can be properly applied the term invention. Merely cuirassing the sides of a vessel with iron armor which is the only substantial difference between the broadside iron-clad and the old wooden ship it is designed to supersede can with no propriety be called an invention. It was an ancient expedient to build the sides of warvessels much thicker than those of commercial ships, and far thicker than mere strength required. The design was, as now with iron-clads, to furnish protection against an enemy's shot. Moreover, descriptions or drawings of very many ancient vessels still exist, in which the sides had been made by this process of cuirassing (for such it may be called) quite as impervious to the artillery then brought against them, as is the present. iron armor of the famous La Gloire and Warrior to the most powerful naval guns in use at the time the latter vessels were constructed. Or, to put the matter in other words, wooden James relates an engagement which took place just seventy years ago off the coast of Flanders, between the English ship Glatton, which was built of remarkably stout timber, and four French frigates and two corvettes, a brig and a cutter, — her fifty-six guns "in strong sides "being altogether too much for their two hundred and twenty. Blackwood's Magazine (November, 1860) says her captain "tumbled his old tub amongst them, taking their fire with comparative impunity, and knocking them about with his guns in a manner which astonished them." The French loss was severe; the English, none killed and only two wounded. And this, too, |