| By the 1820's in the United States,
when steamboats were common on western waters, these boats were mostly powered
by engines built in the West (Pittsburgh, Cincinnati, or Louisville), and of a
distinctive western design specially suited to western needs. The first steam
engines{{U}} (21) {{/U}}practical use in England and the United States
were{{U}} (22) {{/U}}low-pressure design. This was the type first{{U}}
(23) {{/U}}by James Watt, then manufactured by the firm of Boulton and
Watt. Steam was{{U}} (24) {{/U}}in a large, double-acting vertical
cylinder, but the steam reached only a few pounds of pressure per square inch.
It was low-pressure engines of this type that{{U}} (25) {{/U}}first introduced
into the United States by Robert Fulton. He{{U}} (26) {{/U}}such a Boulton and
Watt engine from England to run the Clermont. But this type of engine was
,expensive and complicated,{{U}} (27) {{/U}}many precision-fitted moving
parts. The engine that became standard on western steamboats was of a different and{{U}} (28) {{/U}}design. It was the work primarily of an unsung hero of American industrial progress, Oliver Evans (1755-1819), the{{U}} (29) {{/U}}son of a Delaware farmer. Evans early became{{U}} (30) {{/U}}by the possibilities of mechanized production and steam power. As early as 1802 he{{U}} (31) {{/U}}a stationary steam engine of high-pressure design in his mill. Engines of this type were not{{U}} (32) {{/U}}, but before Evans they were generally considered{{U}} (33) {{/U}}and dangerous. Within a decade the high-pressure engine, the new type, had become standard on western waters. Critics{{U}} (34) {{/U}}of western conditions often attacked it as wasteful and dangerous. But people who really knew the Ohio, the Missouri, and the Mississippi{{U}} (35) {{/U}}, with good reasons, that it was the only engine for them. In{{U}} (36) {{/U}}western rivers the weight of vessel and engine{{U}} (37) {{/U}}important; a heavy engine added to the problem of navigation. The high-pressure engine was{{U}} (38) {{/U}}lighter in proportion to horsepower, and, with less than half as many moving parts, was much easier and cheaper to repair. The main advantages of low-pressure engines were safe operation and {{U}}(39) {{/U}}of fuel consumption,{{U}} (40) {{/U}}of which meant much in the West.. |