her important feature, the turret, was the invention of another head than his. In 1841 Theodore R. Timby made a model of an iron turret, and two years later he filed a caveat in the U. S. Patent Office "for a revolving metallic tower, and for a revolving tower for a floating battery to be propelled by steam." In the same year (1843) he made and exhibited an iron model which combined all the essential principles of his invention, and a short time later another which he sent to the Emperor of China at the hands of the American minister, Mr. Cushing. A committee of Congress made a report to the Secretary of War in 1848, recommending the adoption of the Timby system. Nothing was done in the matter until the outbreak of the civil war, when Timby brought out a new model and secured a patent for "a revolving tower for offensive and defensive warfare, whether used on land or water." His original plan was for a revolving turret 40 feet in diameter, to be pierced for six guns and to make a complete revolution in one minute, the guns to be fired as they came in range of the object to be reached. In accordance with this plan a shot would be delivered every ten seconds. The constructors of the Monitor recognized the validity of Mr. Timby's claim and paid him liberally for the right to use his invention.
In England in 1855 Captain Cowper Coles invented and patented a cupola or turret which was afterwards applied to the war steamer Royal Sovereign, a wooden vessel originally built as a three-decker. Owing to the fact that the Royal Sovereign was not purposely built for use as a turret ship, the new principle was tried under disadvantages; in 1864 she was put out of commission and ordered to be placed among the reserved ships, although many officers contended that she was then the most powerful ship in the British navy. In 1866 Lord Derby's government ordered the construction of four iron-clad turret ships of 4,000 tons burthen each and corresponding steam power. The
