THE GROWTH OF THE STEAM-ENGINE. 261 



improving the details of mill-work, and with such success as to 

 reduce the cost of attendance one-half, and also to increase the fine- 

 ness of the flour made. 



In 1785 he applied for, but was refused, a patent for a steam- 

 carriage. 



In 1800 or 1801, Evans, after consulting with Prof. Robert Patter- 

 son, of the University of Pennsylvania, and getting his approval 

 of the plans, commenced the construction of a steam-carriage, to be 

 driven by a non-condensing engine. 



He soon concluded, however, that it would be a better scheme, 

 pecuniarily, to adapt his engine, which was novel in form and of 

 small first cost, to driving mills ; and he accordingly changed his 

 plans, and built an engine of six inches diameter of cylinder and 

 eighteen inches stroke of piston, which he applied with perfect suc- 

 cess to driving a plaster mill. 



51. This engine (Fig. 27), which he called the " Columbian engine," 

 was of a peculiar form. 



The beam is supported at one end by a rocking column ; at the 

 other it is attached directly to the piston-rod, while the crank lies 

 beneath the beam, the connecting-rod being attached to the latter at 

 about the middle point. 



The head of the piston-rod is compelled to rise and fall in a ver- 

 tical line by the " Evans parallelogram," a kind of parallel motion 

 very similar to one of those designed by Watt. 



52. Subsequently, Evans continued to extend the application of 

 his engine and to perfect its details, and, others following in his track, 

 the non-condensing engine is to-day fulfilling the predictions which 

 he made seventy years ago, when he said : 



" I have no doubt that my engine will propel boats against the currents of 

 the Mississippi, and wagons on turnpike-roads, with great profit. . . . 



" The time will come when people will travel in stages moved by steam- 

 engines, from one city to another, almost as fast as birds can fly fifteen or 

 twenty miles an hour. A carriage will start from Washington in the morning, 

 the passengers will breakfast at Baltimore, dine at Philadelphia, and sup at 

 New York the same day. . . . 



" Engines will drive boats ten or twelve miles an hour, and there will be 

 hundreds of steamers running on the Mississippi, as predicted years ago." 



53. In 1804 Oliver Evans completed a flat-bottomed boat (Fig. 28), 

 to be used at the Philadelphia docks, and, mounting it upon wheels, 

 drew it by its own steam-engine to the river-bank. Launching the 

 craft, he propelled it down the river, using its steam-engine to drive 

 its paddle-wheels. Evans's "oructor amphibolis" as he named the 

 machine, was the first road-locomotive that we find described after 

 Cugnot's time. Evans asserted that carriages propelled by steam 

 would soon be in common use ; and offered a wager of three hundred 



