Her advent into the navy marks an epoch—the inauguration of the successful manufacture in the United States of American rolled steel ship-plating, equal to the best in the world, as shown by the most rigid government tests. The _Dolphin_, is the first vessel, whether for naval or commercial purposes, that is built entirely of steel of domestic manufacture, and is the pioneer representative of other similar industries which will be developed as the rehabilitation of the navy proceeds. She has proved herself eminently successful, and is the fastest sea-steamer of her displacement built in the United States, with perhaps the exception of the steam-yacht _Atalanta_. She is a stanch vessel of great structural strength, and does credit to the ship-building profession of the country. Of the additional cruisers authorized by the late acts of Congress, particulars will be found in the Notes. In one of the larger vessels the type of the _Atlanta_ will be reproduced on a larger scale, while the other vessel of the same class will be provided with a poop and top-gallant forecastle, and will carry her forward and after guns on sponsons, by which means fire ahead and astern will be secured. This will make it necessary to limit the power of the battery of the second vessel to 6-inch guns, as the 8-inch gun cannot conveniently be carried on sponsons in a vessel of 4000 tons displacement. The heavy gun-boat will carry six 6-inch guns, the forward and after ones on sponsons; and the light gun-boat will carry four of the same guns. In the construction of these additional vessels advantage has been taken of all our experience in our initial effort, and of whatever developments may have been made by others since the earlier vessels were designed. The absolute departure from the old standards is apparent in material, in armament, in speed, and in rig. The causes that have led to this change in material may be found, first, in the change that has taken place in ordnance. The introduction of the rifled cannon, and its subsequent development, have increased very much the weight of this part of the equipment of a vessel-of-war, and the necessity of accommodating the stowage of charges of powder much increased in size, and of ammunition for the secondary batteries, which must be most liberally supplied, makes an absolute demand on an increased portion of space. Again, the increased speed now considered indispensable makes a similar demand for space, and carries with it as well an increased proportion of the total displacement. In a wooden hull it would be impossible to reconcile these demands, in consequence of the weight of the hull itself.