>-")4 TUTU T LAU B01LEK, SUPERHEATING STEAM, 



of Mr. Robert Stephenson on the construction of the * Rocket ' 

 engine : ' After the opening of the Stockton and Darlington, 

 and before that of the Liverpool and Manchester Railway, my 

 father directed his attention to various methods of increasing 

 the evaporative power of the boiler of the locomotive engine. 

 Amongst other attempts, he introduced tubes (as had before 

 been done in other engines) small tubes containing water, by 

 which the heating surface was materially increased. Two en- 

 gines with such tubes were constructed for the St. Etienne 

 Railway, in France, which was in progress of construction in 

 the year 1828 ; but the expedient was not successful ; the tubes 

 became furred with deposit, and burned out. 



" 'Other engines, with boilers of a variety of construction, 

 were made, all having in view the increase of the heating sur- 

 face, as it then became obvious to my father that the speed of 

 the engine could not be increased without increasing the evapo- 

 rative power of the boiler. Increase of surface was in some 

 cases obtained by inserting two tubes, each containing a sepa- 

 rate fire, into the boiler; in other cases the same result was 

 obtained by returning the same tube through the boiler ; but it 

 was not until he was engaged in making some experiments, 

 during the progress of the Liverpool and Manchester Railway, 

 in conjunction with Mr. Henry Booth, the well-known secretary 

 of the company, that any decided movement in this direction 

 was effected, and that the present multitubular boiler assumed 

 a practicable shape. It was in conjunction with Mr. Booth 

 that my father constructed the ' Rocket ' engine. 



" * 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 steam- 



