500 INVENTION OF THE STEAM-BLAST. APPENDIX. 



places, was not considered as objectionable on a private rail- 

 road. The tube through the boiler having been increased, there 

 is now no longer any occasion for the action of the steam to 

 assist the motion of the heated air in the chimney. The steam 

 thrown in this manner into the chimney acts as a trumpet, and 

 certainly makes a very disagreeable noise. Nothing, however, is 

 more easy to remedy, and the very act of remedying this defect 

 will also be the means of economising the fuel" (pp. 292-3). 1 



Mr. Wood then proceeds to show how the noise caused by the 

 blast, how in fact the blast itself, might be effectually prevented 

 by adopting the expedient employed in the Wylam engine ; which 

 was, to send the exhaust steam, not into the chimney (where 

 alone the blast could act with effect by stimulating the draught), 

 but into a steam-reservoir expressly provided for the purpose. 

 His words are these : " Nothing more is wanted to destroy the 

 noise than to cause the steam to expand itself into a reservoir, and 

 then allow it to escape gradually to the atmosphere through the 

 chimney. Upon the Wylam railroad the noise was made the 

 subject of complaint by a neighbouring gentleman, and they 

 adopted this mode, which had the effect above mentioned" 

 (p. 294). 



We think this ought to be perfectly conclusive as to the 

 Wylam engine that it had no blast, and that it contained an 

 arrangement for the express purpose of preventing any blast. 

 And thus we dismiss Mr. Hedley's claim. 



It is curious to find that Mr. Nicholas Wood continued to 

 object to the use of the steam-blast down even to the time 

 when the Liverpool and Manchester Railway Bill was before 

 Parliament in 1825. Hence Mr. Wood, in his evidence before 

 the Committee on that Bill in 1825, said : " Those engines [at 

 Killingworth] puff very much, and the object is to get an increased 

 draught in the chimney. Now (by enlarging the flue-tube and 

 giving it a double ,turn through the boiler) we have got a suf- 

 ciency of steam without it, v and I have no doubt by allowing 



1 These passages will be found in | portant for our present purpose that, 



the first edition of Mr. Wood's work, , in the year 1825, long before the 



published in 1825, The subsequent I Liverpool and Manchester line was 



editions do not contain them. A ! opened, Mr. Wood should have so 



few years' experience wrought great j clearly described the steam-blast which 



changes of opinion on many points had been in regular use for more than 



connected with the practical working j ten years in all Stephenson's locomo- 



of railways, and Mr. Wood altered his ' tives employed in the working of the 



text accordingly. But it is most im- Killingworth railway. 



