Page:Collier's New Encyclopedia v. 09.djvu/90

STEAMBOAT 64 STEAM HAMMER This last mentioned boat was the first American steam vessel that can be pro- nounced a success. It made its first trip to Burlington in July, 1788. But, after The oldest and simplest consists of a bent tube partially filled with mercury, one end of which springs from the boiler, so that the steam rising in the SYMINGTON'S STEAMBOAT, 1801 all, it was not till after the opening of the 19th century that steam navigation started into actual life. In 1801 Syming- ton designed a boat for towing, which at- tained a speed of 3^/^ miles an hour. In 1807 Robert Fulton, an American, in conjunction with one Robert R. Living- THE GREAT EASTERN ston, built the "Clermont" and estab- lished a regular packet service between New York and Albany. STEAM NAVIGATION. See Ship and Shipping. See Steam Turbine and Steam. STEAMEB, or RACE-HORSE DUCK {Micropterus brachypterus) , a species of marine duck from 35 to 40 inches in length, distinguished by its small, short wings, and the swiftness with which it paddles over the surface of the water. It is found in Patagonia and the Falk- land Islands. STEAM GAUGE, an instrument at- tached to a boiler to indicate the pres- sure of steam. There are many varieties. tube forces up the mercury in propor- tion to the amount of pressure. STEAM HAMMER, a hammer worked by means of steam. The idea of a steam hammer seems to have occurred first to James Watt) who patented it in 1784. William Deverell also took out a patent for a steam hammer in 1806; but it does not appear that in either case the idea was carried into operation. In 1839 James Nasmyth invented the steam ham- mer called after him, and patented it in 1842. In the older forms of steam ham- mer, the hammer head, attached to one end of a lever, was raised by the action of a cog wheel or cam acting on the other end of the lever, and was then al- lowed to fall by its own weight. Ham- mers of this description are often called steam tilts. In Nasmyth's hammer the head is attached to the piston rod of an inverted cylinder supported vertically, and the piston is raised by the action of the steam admitted into the cylinder below the piston. The hammer is al- lowed to fall by its own weight, or is driven downward with still greater ve- locity by the action of steam admitted into the cylinder above the piston. The admission of steam into the cylinder "s regulated by a side valve worked by a lever, and the force of the stroke can be controlled to such an extent by reg- ulating the admission of steam, that the largest hammer can be made to crack a nut, or to come down on a mass of iron with a momentum of many hundred foot tons. The weight of the hammer ranges from about 200 pounds to 25 tons; and the object to be struck is placed on an anvil consisting of a slab of iron resting on a huge mass of piles and concrete, which frequently descends a great depth