Page:Report from the Select Committee on Steam Carriages.pdf/129



Mr. Richard Trevithick. 12 August, 1831. four to one, and as ten to one on the Atmospheric Engines.

Have you lately paid attention to Steam Carriages on common roads?—I have noticed the Steam Carriages very much; I have been abroad for a good many years, and had nothing to do with them until lately, but I have it in contemplation to do a great deal on common roads; Railroads are useful for speed, and for the sake of safety, but not otherwise, every purpose would be answered by steam on common roads.

Is your machine applicable to Steam Carriages?—It is chiefly for that purpose, it works without water; now the Manchester Carriages use four tuns a day, two tuns that they take in when they start, and two that they take in midway of their journey; there is that weight to carry, and the loss of time.

You conceive Steam Carriages to be applicable to common purposes?—Yes, to every purpose a horse can effect.

Have you any plan particularly applicable to that purpose?—Yes. I have taken out a patent for that purpose; this, the Plan which I produce, [producing the same,] will show the principle. I built a twenty-horse engine in Cornwall, in order to try this: this I produce is for a Ship Engine. [Mr. Trevithick explained to the Committee the different parts of the Machine on the Plan.] The bursting of boilers has been occasioned by the boilers being left under guage neglected to be charged with water, and. I believe, by their getting foul and incrusting with salt from using salt-water; the low-pressure Engines have burst as well as the high pressure; if the tubes of the boilers are heated red-hot, and the Engine is standing at the time the water is still in, the boiler is quiet; but on the Engine setting to work, a discharge of Steam from the boiler to the cylinder causes a great ebullition in the boiler, and the water splashing over the hot sides makes a superabundant generation of steam. The space that would be filled instantaneously from the hot tubes being suddenly cooled, the space occupied by that superabundance would fill three hundred times the space usually allowed for