TREVITHICK. 129 



cessful completion, being at onco a melancholy monument of his 

 folly and his skill. 



After this unfortunate failure, Trevithick commenced many 

 schemes; among others, his attention was directed towards the 

 introduction of iron tanks and buoys into the Royal Navy. On first 

 representing the importance of this to the Admiralty, the objection 

 was raised, that perhaps, in the case of the tanks, iron would be 

 prejudicial to the water, and consequently to the health of the 

 crews ; Trevithick was therefore requested to consult Abernethy 

 upon the subject, which he accordingly did, and received for his 

 answer the following characteristic reply : " That the Admiralty 

 ought to have known better than to have sent you to me with such 

 a question." He likewise, about this period, contributed largely to 

 the improvement and better working of the Cornish engines, and to 

 him the merit is due of introducing into these engines the system of 

 high -pressure steam, and of inventing in the year 1804 the cylin- 

 drical wrought iron boiler, (now known as the Cornish boiler,) in 

 which he placed the tire inside instead of outside, as had been the 

 practice before his time. 



Trevithick also appears to have been among, if not the very first 

 to employ the expansive principle of steam. In the year 1811-12 

 he erected a single-acting engine of 25 inches cylinder at Hull- 

 Prosper in Gwithian, with a cylindrical boiler, in which the steam 

 was more than 401bs. on the square inch above atmospheric pres- 

 sure ; and the engine was so loaded that it worked full seven-eighths 

 of the stroke expansively. In this he seems to have preceded 

 Woolf by several years. It is also stated by Mr. Gordon in his 

 ' Treatise on Elementary Locomotion,' that Trevithick was the first 

 to turn the eduction-pipe into the chimney of the locomotive to 

 increase the draught.* 



We now come to the most romantic and stirring period of Tre- 

 vithick's career. In 1811 M. Uville", a Swiss gentleman at that time 

 living in Lima, came to England to see if he could procure ma- 

 chinery for clearing the silver mines, in the Peruvian mountains, of 

 water. Watt's condensing engines were, however, of too ponderous 

 a nature to be transported over the Cordilleras on the backs of the 

 feeble llamas, and Uville* was about to give the matter up in despair, 

 when, on the eve of his departure from this country, he chanced to 

 see a small working model of Trevithick's engine in a shop window 

 near Fitzroy Square. This model he carried out with him to Lima, 

 and had the satisfaction of seeing it work successfully on the high 

 ridge of the Sierra de Pasco. Uvill6 now returned to England to 

 procure more engines of the same kind, but he was a second time 

 almost forced to give the matter up ; for Boulton and Watt, the 



* Phil. Mag. and Annals of P7iilosophy, August, 1831, in a letter to Kichard 

 Taylor, F.S.A., by W. Jory Henwood, F.G.S. 



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