One of these boats, named, after her owner, the _Robert F. Stockton_, was built of iron by Messrs. Laird of Birkenhead, and launched in 1838. She was 70 feet in length, 10 feet wide, and drew 6 feet 9 inches of water. Her cylinders were 16 inches diameter with 18 inches stroke, and her propeller 6 feet 4 inches in length. On her trial trips on the Thames, made in January of the following year, she accomplished a distance of 9 miles (over the land) in 35 minutes with the tide, thereby proving the speed through the water to be between 11 and 12 miles an hour. On her second trial, between Southwark and Waterloo bridges, she took in tow four laden barges, with upright sides and square ends, having a beam of 15 feet each, and drawing 4 feet 6 inches of water. One of these was lashed on each side, the other two being towed astern, and, though the weight of the whole must have been close upon 400 tons, and a considerable resistance was offered, also, by their form, the steamer towed them at the rate of 5½ miles an hour in slack water, or in 11 minutes between the two bridges, a distance of 1 mile. [Illustration] These experiments having been considered in every way satisfactory, the _Robert F. Stockton_, of which the following is an illustration, left England for the United States in the beginning of April 1839, under the command of Captain Cram, of the American merchant service. Her crew consisted of four men and a boy, and, having accomplished the voyage under sail in forty days, Captain Cram was presented with the freedom of the city of New York for his daring in crossing the Atlantic in so small a craft, constructed only for river navigation. [Sidenote: His vessel a complete success;] In 1840, Captain Stockton sold this vessel to the Delaware and Raritan Canal Company, permission having been obtained (being British built) by a special Act of Congress, to run her in American waters, and her name was at the same time changed to that of the _New Jersey_. For many years she was in constant work as a steam-tug on the rivers Delaware and Schuylkill during the winter months, as she was capable of towing through the drift ice, where paddle-wheel steamers are of little use. [Sidenote: and the first “screw” used for commerce in America.]