against the effect of shells.
The remaining ten built at the Navy Yards were of somewhat less size, but to be of great speed; and as nearly all of these were of full-sail power.
they were expected to maintain their positions at sea for at least three months, and to be used on the most distant stations.
Among the wonders of the age at that time were built a set of vessels called the Miantonomoh class — a wooden vessel designed by the naval constructors, and built at the Navy Yards with Ericsson turrets, the machinery designed by Engineer-in-chief B. F. Isherwood, chief of the Bureau of Steam Engineering; with a high rate of speed, perfect ventilation, impregnable, and with the enormous battery of four 15-inch guns, all combined in a vessel of the moderate rate of 1,560 tons, drawing only 12 feet of water.
Others of the same type, with increased tonnage and of still higher speed, were also in the course of construction, and the Federal Government had, apparently, realized at last