488 ROBERT STEPHENSON'S NARRATIVE. APPENDIX. 



" Another important improvement was introduced in this en- 

 gine. The eduction steam had hitherto been allowed to escape 

 direct into the open atmosphere ; but my father, having observed 

 the great velocity with which the waste-steam escaped, com- 

 pared with the velocity with which the smoke issued from the 

 chimney of the same engine, thought that by conveying the 

 eduction steam into the chimney and there allowing it to escape 

 in a vertical direction, its velocity would be imparted to the 

 smoke from the engine, or to the ascending current of air in the 

 chimney. The experiment was no sooner made than the power 

 of the engine became more than doubled ; combustion was 

 stimulated, as it were, by a blast ; consequently the power of 

 the boiler for generating steam was increased, and, in the same 

 proportion, the useful duty of the engine was augmented. 



" Thus in 1815 my father had succeeded in manufacturing an 

 engine which included the following important improvements 

 on all previous attempts in the same direction : simple and 

 direct communication between the cylinder and the wheels 

 rolling upon the rails ; joint adhesion of all the wheels, attained 

 by the use of horizontal connecting-rods ; and, finally, a beautiful 

 method of exciting the combustion of fuel by employing the 

 waste-steam which had formerly been allowed uselessly to 

 escape. It is, perhaps, not too much to say that this engine, 

 as a mechanical contrivance, contained the germ of all that has 

 since been effected. It may be regarded, in fact, as a type of 

 the present locomotive engine. 



" In describing my father's application of the waste-steam for 

 the purpose of increasing the intensity of combustion in the 

 boiler, and thus increasing the power of the engine without 

 adding to its weight, and while claiming for this engine the 

 merit of being a type of all those which have been successfully 

 devised since the commencement of the Liverpool and Man- 

 chester Kailway, it is necessary to observe that the next great 

 improvement in the same direction, the " multitubular boiler," 

 which took place some years later, could never have been used 

 without the help of that simple expedient the steam-blast, by 

 which power only the burning of coke was rendered possible. 



" I cannot pass over this last-named invention of my father's 

 without remarking how slightly, as an original idea, it has been 

 appreciated ; and yet how small would be the comparative value 

 of the locomotive engine of the present day without the applica- 

 tion of that important invention ! 



