The testimony of Captain W.H.  Hall, R.N., in command of the iron frigate Nemesis, in the Chinese war, was still more conclusive in favor of iron.  He stated, “that in one action the Nemesis was hit fourteen times,” and that one shot “went in at one side and came out at the other, and there were no splinters; in case of that shot, it went through just as if you put your finger through a piece of paper:  nothing could have been more easily stopped than I could have stopped that shot in the Nemesis”; that, “several wooden steamers were employed in that service, and they were invariably obliged to lie up for repairs, whilst I could repair the Nemesis in twenty-four hours and have her always ready for service.”  The Nemesis was a common iron steamer, and not a mail-clad steamship.

As respects the strength and durability of these steamers, although accidents have occurred from defective materials, it is in proof that the Tyne and Great Britain ran ashore and remained for months exposed to the open sea without going to pieces, and were finally rescued,—­that the Persia struck on an iceberg, filled one of her compartments with water, and came safe to port,—­that the North America and Edinburgh went at full speed upon the rocks near Cape Race and yet escaped,—­and that the Sarah Sands, while transporting troops to India, took fire, that in consequence the interior and contents of one of her compartments were entirely consumed, that her magazine exploded, and that she then encountered a ten days’ gale, and after this exposure to such a series of calamities she reached her port without losing one of her crew or passengers.

The ambition of England to maintain her ascendancy upon the deep has led her to disregard the advice of her Defence Commissioners, who recommended a different class of mail-clad steamers, to measure but two thousand tons and to draw but sixteen feet of water,—­a class admirably adapted to the sea-ports and requirements of the United States.  And singular as it may appear, by some coincidence at a moment when our country requires this class of steamers, the enterprise of Boston is completing two iron steamers whose dimensions and draught of water conform to the recommendation of the British Commissioners,—­steamers which are nearly ready for launching, but which, if they can receive, before they leave the stocks, additional plates of iron, would doubtless prove the most useful and efficient mail-clad vessels which have yet been constructed.

The stranger who would inspect these beautiful vessels may seat himself at almost any hour of the day in the cars at the foot of Summer Street, and in twenty minutes find himself at a point a little north of the Perkins Asylum for the Blind.  A walk of five minutes more will bring him to a secluded yard sloping gently towards the water, where he will find extensive offices, and two large buildings which cover the vessels upon the stocks.

As he approaches these structures, he will notice many plates of superior iron from the rolling-mills of Baltimore, combining the toughness and strength and other excellences of the best Pennsylvania iron; he will notice, too, immense ribs and beams of iron, and hear the incessant din of hammers riveting the sides and boilers.