The specification also shows the application of the high-pressure engine on the same principle to the driving of a sugar-mill, or for other purposes where a fixed power is required, dispensing with condenser, cistern, air-pump, and cold-water pump. In the year 1803, a small engine of this kind was erected after Trevithick's plan at Marazion, which worked by steam of at least 30 lbs. on the inch above atmospheric pressure, and gave much satisfaction. The first experimental steam-carriage was constructed by Trevithick and Vivian in their workshops at Camborne in 1803, and was tried by them on the public road adjoining the town, as well as in the street of the town itself. John Petherick, a native of Camborne, who was alive in 1858, stated in a letter to Mr. Edward Williams that he well remembered seeing the engine, worked by Mr. Trevithick himself, come through the place, to the great wonder of the inhabitants. He says, "The experiment was satisfactory only as long as the steam pressure could be kept up. During that continuance Trevithick called upon the people to 'jump up,' so as to create a load on the engine; and it soon became covered with men, which did not seem to make any difference to the power or speed so long as the steam was kept up. This was sought to be done by the application of a cylindrical horizontal bellows worked by the engine itself; but the attempt to keep up the power of the steam for any considerable time proved a failure." Trevithick, however, made several alterations in the engine which had the effect of improving it, and its success was such that he determined to take it to London and exhibit it there as the most recent novelty in steam mechanism. It was successfully run by road from Camborne to Plymouth, a distance of about ninety miles. At Plymouth it was shipped for London, where it shortly after arrived in safety, and excited considerable curiosity. It was run on the waste ground in the vicinity of the present Bethlehem Hospital, as well as on Lord's cricket-ground. There Sir Humphry Davy, Mr. Davies Gilbert, and other scientific gentlemen inspected the machine and rode upon it. Several of them took the steering of the carriage by turns, and they expressed their satisfaction with the mechanism by which it was directed. Sir Humphry, writing to a friend in Cornwall, said, "I shall soon hope to hear that the roads of England are the haunts of Captain Trevithick's dragons--a characteristic name." After the experiment at Lord's, the carriage was run along the New-road, and down Gray's-Inn Lane, to the premises of a carriage-builder in Long Acre. To show the adaptability of the engine for fixed uses, Trevithick had it taken from the carriage on the day after this trial and removed to the shop of a cutler, where he applied it with success to the driving of the machinery.