The boat was launched in October of that year and given the pedantic name of _Demologos_, which was simplified to _Fulton the First_. The war ended before the vessel could be tested, and she became a receiving ship. Her machinery was arranged to drive a large paddle-wheel, placed amidships and working in a tunnel in the hull. She was to carry twenty guns, not forty-four as sometimes stated, and furnaces for red-hot shot, and was to travel at a rate of four miles an hour. Besides her deck armament it was proposed that she should have two submarine guns suspended from each bow, which were to send a hundred-pound ball into an enemy’s hull ten or twelve feet below the water-line. Her machinery was intended to pump a tremendous column of water upon the enemy’s decks and through the latter’s portholes. Her gun-deck was completely covered over so that no hostile shot could reach it from above. Her wooden walls were five feet in thickness, and capable of withstanding the heaviest shot of the day. The dimensions of this remarkable craft were: length, 156 feet; beam, 56 feet; and depth, 20 feet; but her draught, loaded, was only 10 feet. The water-wheel, the position of which is indicated in the centre of the accompanying plan of the gun-deck, was 16 feet in diameter, and had blades or buckets measuring 14 feet with a dip of 4 feet. The cylinder of the engine measured 48 inches, and the stroke was of 5 feet. The boiler was 22 feet long by 12 feet beam, and 8 feet deep. The gross tonnage of the vessel is set down at 2,475 tons. The ship was two-masted, and could steam either end foremost. She was built at Brown’s yard at New York, in four months after her keel was laid, and given her machinery and guns at Fulton’s works on the North River. Another vessel, destined like the _Demologos_ never to see active service, but which, nevertheless, was the first iron-clad steamer actually built, was the ship designed, in 1841, by Edwin A. Stevens, a son of John Stevens, at the time that hostilities were feared between England and the United States. Mr. J. Elfreth Watkins, in an address before the Philosophical Society of Washington, in 1892, said:--“As thick armour plate could not be made at that date, he devised the method of armour plating in laminæ, or plates laid over each other and riveted. He then made a series of experiments to determine the thickness of plating required to resist the different sizes of balls then in use. From these experiments, which were made at Bordentown, N.J., in the summer of 1841, he made the deduction that a target of iron 4½ inches thick would resist a 64 lb. shot, at that time the heaviest ball used in our navy.” This standard of thickness was afterwards adopted by European naval architects for warship iron armour.