Steam had not yet succeeded in asserting its undivided sway; but the _Iroquois_ and her mates marked a stage in the progress, for they carried sails really as auxiliary, and were intended primarily to be fast steamers, as speed was reckoned in their time. The larger vessels of the service were acceptedly slow under steam. They had it chiefly to fight with, and to help them across the places where wind failed or weakened. These corvettes carried sails with a view to saving coal, by utilizing the well-defined wind zones of the ocean when fair for their course. Though the practical result for both was much the same, the underlying idea was different. In the one, sail held the first place; in the other, steam; and it is the idea which really denotes and maintains intellectual movement and material progress. This was represented accordingly in the rig adopted. Like a ship, they had three masts, yes; but only the two forward were square-rigged, and on each of them but three sails. The lofty royals were discarded. The general result was to emphasize the design of speed under steam, and the use of sails with a fresh, fair wind only; a distinct, if partial, abandonment of the "auxiliary" steam reliance which so far had governed naval development. It may be added that the shorter and lighter masts, by a common optical effect, increased the impression of the vessel's length and swiftness, as was the case with the old-time sailing-frigate when her lofty topgallant-masts were down on deck. Under sail alone the _Iroquois_ could never accomplish anything, except with a fair wind. We played with her at times, on the wind and tacking, but she simply slid off to leeward--never fetched near where she looked. Consonant with the expedient of using sails where the wind served, the screw could be disconnected from its shaft and hoisted; held in position, clear of the water, by iron pawls. In this way the hinderance of its submerged drag upon the speed of the ship was obviated. We did this on occasions, when we could reckon on a long period of favorable breezes; but it was a troublesome and somewhat anxious operation. The chance of a slip was not great, but the possibility was unpleasant to contemplate. When I add that for armament we carried one 100-pounder rifled gun on a pivot, and four 9-inch smooth-bore shell guns--these being the naval piece which for the most part fought the War of Secession, then just closed--I shall have given the principal distinguishing features of a class of vessel which did good service in its day, and is now a much of the past as is the Spanish Armada. Yet it is only forty years since.