portance of steam as a motive power had become established, the early side-wheelers were built,—first the Mississippi and Missouri, and later the Powhatan, Susquehanna, and Saranac.
The Powhatan and Susquehanna, at the time they were launched, in 1850, were the most efficient naval vessels afloat.
Next came the six screw-frigates, which were built in 1855, and 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 Roan the matter of ordnance, as in ships, the navy had been making active progress.
In the old sailing vessels, the 32 pounder, which was simply a development of the 18s and 24s of 1812, and the Viii-inch shell-gun were still the usual guns.
Since 1850, the powerful Dahlgren smooth-bore shell-guns had been introduced, and the new steam-frigates and sloops were armed with them.
The Ix-inch guns of this description were mounted in broadside, and the Xi-inch (with a few X-inch) on pivots.