Page:Popular Science Monthly Volume 12.djvu/558

540 make the trip from St. Louis to New Orleans—about 1,200 miles—in four days, and can make, in still water, more than twenty miles an hour.

In the East, we have a form of engine which is distinctively known as the American steamboat-engine. It is shown in Fig. 62.



This engine is recognized throughout the engineering world as one of the most complete and thoroughly perfected of known types of steam-engine.

106. This peculiarly effective and easy-working engine, and the equally peculiar vessel (Fig. 63) which is usually impelled by it, are, in all their peculiarities, characteristically American.

The "skeleton-beam," which is one of the prominent features, was first used by Robert L. Stevens on the ferry-boat Hoboken, in 1822.

The valve-gear is usually that known as the "Stevens valve-gear." It was invented by Messrs. Robert L. and Francis B. Stevens, in 1841. The "gallows-frame" took its present form in the hands of