84 



MATHEMATICAL AND PHYSICAL SCIENCE. 



[Diss. VI. 



write those often quoted lines in the Botanic Garden 

 (canto i. line 290) : 



" Soon shall thine arm, unconquered Steam, afar 

 Drag the slow barge, or drive the rapid car." 



(385.) A somewhat longer pause now occurs. But in 

 Trevithick 1802 we find Richard Trevithick, a Cornish " cap- 

 and y 1 " . tain " of a mine, taking out a patent along with Vi- 

 patent in vian for the high-pressure steam-engine, and apply- 

 1802. ing it specifically and practically to the movement 

 of carriages or waggons along a railway at Merthyr 

 Tydvil in South Wales. Mr Muirhead informs us 

 that Trevithick saw Murdoch's model at Redruth in 

 Cornwall. But admitting this, it is plain that the 

 idea was much older still, and also that many years 

 elapsed without its ever being brought practically 

 to bear until the year 1804, when Trevithick's loco- 

 motive was actually used. 



(386.) RICHARD TREVITHICK. appears to have been one of 

 Account of the most ingenious men of his time ; but (from the 

 110 ' scanty notices which I have been able to collect 1 ) to 

 have been also of an inconstant speculative disposi- 

 tion, which prevented him from bringing any of his 

 numerous inventions to perfection. Yet he had the 

 good fortune, which so many inventors have missed, 

 of meeting with partners able and willing to assist him 

 in carrying out his designs. Amongst these was 

 Andrew Vivian, with whom in 1802 he took out the 

 patent already mentioned for the construction of high- 

 pressure engines, and their application to the move- 

 ment of carriages along rails or common roads. As 

 Applies the first practical employer of high-pressure steam of 

 sure?team 60 to 80 lb> P ressure n the square inch, Trevithick 

 to locomo- deserves especial notice. He borrowed the notion of 

 tiyes on it, as well as the ingenious invention of the four- way 

 coc k' ^ rom an ^ sc heme of Leupold's, but he over- 

 came for the time the prejudice which had always 

 existed even in the mind of Watt against its adop- 

 tion. His earliest engine is stated to have been con- 

 nected with a common stage coach which ran on the 

 streets of London ; but his more successful and im- 

 portant effort was made in dragging waggons along 

 the Merthyr Tydvil railway in South Wales, which 

 was successfully tried on the 21st February 1804, 

 when the engine drew carriages containing ten tons 

 of bar iron for a distance of nine miles at the rate of 

 five miles an hour. This was unquestionably the 

 first successful example of this modern species of 

 locomotion. 

 (387.) jf we look mor e closely at the means by which it 



Account of v i -, ,, T .. * 



his engine. was accomplished, we find still more reason to com- 

 mend the sagacity of the inventor, and to wonder at 

 the interval of nearly thirty years which elapsed be- 

 fore the general adoption of his plan. " A square 

 iron case containing the boiler and cylinder was placed 

 behind the large or hinder wheels of the carriage, and 

 was attached to a frame supported from the axles of 



those wheels. The cylinder was in a horizontal po- 

 sition, and the piston-rod was projected backwards 

 and forwards in the line of the road towards the front 

 of the carriage. Across the square frame, supported 

 by the wheels of the carriage, an axle was extended 

 reaching a little beyond the frame on each side ; this 

 axle was cranked in the middle, in a line with the 

 centre of the cylinder, and a connecting-rod passing 

 from the end of the piston turned this axle round, 

 and produced a continued rotatory motion of it when 

 the piston was moved backwards and forwards in the 

 cylinder ; upon both ends of this axle cog-wheels 

 were fixed, which worked into similar cog-wheels 

 upon the axles of the wheels of the carriages, so that 

 when a rotatory motion was produced in the cranked 

 axle by the piston-rod it was communicated to the 

 axle of the larger or hinder wheels of the carriages, 

 and these wheels being fixed upon and turning round 

 with the axle, gave a progessive motion to the car- 

 riage. Upon one end of the axle was fixed a fly- 

 wheel to secure a rotatory motion in the axle at the 

 termination of each stroke." 2 



We here find the cranked axle and the horizontal (388.) 

 cylinder of modern locomotives, both of which were 

 departed from by Trevithick himself, probably in 

 consequence of difficulties of execution. When we 

 add to this plain description, that the fly-wheel was 

 furnished with a break, that the boiler had a safety- 

 valve or a fusible plug beyond the reach of the engi- 

 neer, and that the patent includes the production of 

 " a more equable rotatory motion, .... by caus- 

 ing the piston-rods of two cylinders to work on the 

 said axis by means of cranks at a quarter of a turn 

 asunder," it is scarcely too much to say that nothing 

 material was added to the design of the Locomotive 

 until the invention of the tubular boiler in 1829. 



The Merthyr locomotive blew up, and the preju- (389.) 

 dice against high-pressure steam revived. The in- Trevi- 

 ventor, in the meantime, diverted his attention to . e ex _ 

 other schemes, and continued his profession as apiodes. 

 Cornish mining engineer. 



A singular circumstance opened for Trevithick a (390.) 

 new sphere. A Spanish- American gentleman named His subse 

 Uville, who was engaged in working the silver mines ^ e e r n * n C d~ 

 of Peru, came to England in 1811, with a view to aisappoin 

 discover an engine fit for draining those mines whose ment. 

 high elevation rendered condensing steam-engines 

 working under atmospheric pressure comparatively 

 inert. In London he met accidentally with a model 

 of Trevithick's engine, and having carried it to the 

 heights of Pasco in Peru, and being satisfied with its 

 work, he did not rest until he had returned to Eng- 

 land and transported nine high-pressure engines in 

 1814 to the scene of operations. In 1816 Trevi- 

 thick himself followed, with coining engines and pu- 

 rifying furnaces of his own contrivance. Had he 



1 It is stated that the Society of Civil Engineers have in vain proposed a medal for a biography of Trevithick. 



2 Wood on Railways. This description corresponds with Trevithick's specification and drawings. Repertory of Arts, &c., Se- 

 nd Series, vol. iv. 



