w/z/ua.) Ward 



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Figure 77. — Phineas Davis's device for "promoting combustion &c" in the 

 burning of anthracite coal. Two "fan wheels or vanes revolving within drums 

 [A] in a manner well known to machinists . . ." were turned by a "steam 

 wheel" [B] built "in the same manner nearly as the wind wheels." From U.S. 

 patent, July 29, 1834, restored drawing. National Archives photograph. 



that he worked out so successfully in his "Arabian," 

 as to make it the type of the engines that for several 

 years effectively did the work on the Washington 

 branch as well as the main line of the Baltimore and 

 Ohio Railroad.- 40 It is to be hoped the company will 

 so dispose of the "Arabian" that it shall be perpetually 

 preserved. 



I cannot give a detailed description of the working 

 model, but so much that its general character can be 

 understood. The boiler was a wrought iron mercury 

 bottle, say about 4 inches diameter and 12 inches 

 long; holes were cut in the ends and through them 

 i%-inch inside diameter copper tube brazed to the 

 heads, so that when placed horizontal, as it was in 

 the model, it represented a single-flue cylinder boiler. 

 The steam-engine was a single vertical cylinder, 

 which was placed on a frame extending from one end 

 of the boiler, its piston-rod connected directly to a 

 lever beam, which had its long end journaled to a 

 pair of straddle legs secured by rock joints to the top 

 of the boiler; there were no guides to piston-rods, 

 parallel bars being used instead, the connecting-rod 



working from the short end of the lever beam gave a 

 longer sweep to the crank than the length of the 

 piston stroke. 241 The crank was central on a shaft 

 hung on the frame that carried the steam cylinder, a 

 fly-wheel on each end of the shaft; to the arms of 

 these fly-wheels were deeply grooved stud pulleys, 

 from each of which chain belts ran to corresponding 

 pulleys of a greater diameter on the axle of the carry- 

 ing or driving wheels at or near the other end of the 

 boiler; about the center of this driving axle was a 

 single pulley from which a chain belt ran to one on 

 the front axle, so that all the wheels were connected 

 and the entire weight of the engine made available 

 for traction, with the exception of what was carried 

 on a pair of narrow-tread and narrow-tired guide 

 wheels; they were hung on a lever arrangement so 

 that the driver, with his foot on a treadle, could 

 increase or decrease the pressure on the road. These 

 guide wheels were governed by the driver through a 

 pinion working in a segment of a tooth wheel; on the 



210 The Peter Cooper locomotive also had a vertical steam 

 cylinder. 



2,1 This is a description of the Evans straight-line linkage. 

 However, I have not found a positive attribution of it to Evans 

 before the widely circulated engraved plate of the "Columbian" 

 engine of about 181 3. 



183 



