"'In this instance, as in every other important step in science or art, various claimants have arisen for the merit of having suggested the multitubular boiler as a means of obtaining the necessary heating surface. Whatever may be the value of their respective claims, the public, useful, and extensive application of the invention must certainly date from the experiments made at Rainhill. M. Seguin, for whom engines had been made by my father some few years previously, states that he patented a similar multitubular boiler in France several years before. A still prior claim is made by Mr. Stevens, of New York, who was all but a rival to Mr. Fulton in the introduction of steamboats on the American rivers. It is stated that as early as 1807 he used the multitubular boiler.
"'These claimants may all be entitled to great and independent merit; but certain it is, that the perfect establishment of the success of the multitubular boiler is more immediately due to the suggestion of Mr. Henry Booth, and to my father's practical knowledge in carrying it out.'
"We may here briefly state that the boiler of the 'Rocket' was cylindrical, with flat ends, 6 feet in length, and 3 feet 4 inches in diameter. The upper half of the boiler was used as a reservoir for the steam, the lower half being filled with water. Through the lower part twenty-five copper tubes of 3 inches diameter extended, which were open to the fire-box at one end and to the chimney at the other. The fire-box, or furnace, 2 feet wide and 3 feet high, was attached immediately behind the boiler, and was also surrounded with water."
Stephenson knew of Trevithick's patent of 1802,[185] in which a three-tubed boiler is shown; and it was after that time that Oliver Evans and Fulton tried their experiments, and also the numerous engines with single or return double tube, at work in the principal towns of England prior to 1804,[186] and near his residence in childhood and in manhood.[187]
George Stephenson's Killingworth boiler, "to which he added the steam-blast with such effect," was a copy of Trevithick's boiler and blast, working since 1804 in Newcastle-on-Tyne, and was precisely the boiler described by Stephenson; "in other cases the same result was obtained by returning the same tube through the boiler." This is an admission from Stephenson that Trevithick's patent boiler was the best in use up to about 1828.
A further proof of the indirect public gain from the use of Trevithick's return-tube boiler over a period of thirty years is their having supplied high-pressure expansive steam in the first experiments made with such steam by the Admiralty, at whose request Mr. Rennie and others examined the duty of the Cornish high-pressure expansive engine, and Captain King, R.N., in charge of the Admiralty Department at Falmouth in 1830, gave an order to Harvey and Co. to construct high-pressure steam-boilers for the Government vessel 'Echo'; in 1831 the machinery was put on board the 'Echo' in the Government Dockyard at Plymouth, and included three of Trevithick's return-tube boilers, made of wrought iron, each 5 feet 6 inches in diameter and 24 feet long, with internal return fire-tube 2 feet 2 inches in diameter. The fire-place end of the boiler was 6 feet 9 inches deep by 5 feet 6 inches wide, to give room for the fire-place and ash-pit. The steam pressure was 20 lbs. on the inch above the atmosphere, worked by double-beat valves, 6 inches in diameter, with expansive gear.
This new machinery was fixed under the superintendence of the writer, after which the Government engineers took charge of the vessel, and the writer who had, as the mechanic in charge, worked like a slave, though receiving but 1s. 6d. a day and expenses, was not invited to take any part in the experimental trials, nor ever heard of the result except in the ordinary rumours of Admiralty bungling on board the 'Echo.'
Those boilers were similar to the Trevithick boiler that had served the locomotive in Newcastle and elsewhere from 1801 to 1828, the first steamboat experiments in England, in Scotland, and in America, and the numerous high-pressure engines then at work.