136 



ON THE SETTING OP STEAM BOILERS. 



any rate to the same extent. The first, splitting the draught, 

 or the unequal pull, is entirely done away with, as the gases 

 have an uninterrupted passage from one side to the other 

 and to the chimney. The side flues aro a little larger, and 

 inspection is easier. The chief objection to this type of 

 sotting, which has usually been sufficient to condemn it, is 

 that the boiler is set upon a centre wall, or midfeather as 

 it is called ; and corrosion may easily bo sot up, and go on 

 undiscovered. 



In my opinion, the condemnation of this stylo of setting 

 (that is the wheel draught), on this account only, is most 

 unreasonable ; as it seems to me to be almost as bad to set 

 a boiler on two 4|-inch walls as on one 9-inch, especially 

 as the position of the two walls, being so nearly at the 

 bottom of the shell, is practically as bad for catching damp 

 and leakages as if they were quite at the bottom. 



Not that I advocate the midfeather, as usually constructed, 

 on the contrary, I condemn it ; but I find that the wheel 

 draught lends itself most readily to a system of setting, 

 more perfect and free from objections than any I have yet 

 seen or hoard of (and which I will now proceed to describe) — 

 a system that has proved itself in hundreds of instances 

 successful in the economical generation of steam, because it 

 is based on scientific principles and follows natural laws. 



This is called "Livet's system," from having been in- 

 vented and perfected by M. Livet, a French gentleman 

 who has combined a thorough knowledge of the laws of 

 combustion, and those which govern gaseous fluids, with a 

 practical application of the same to the generation of steam., 

 I am indebted to him for the drawings I have hero, and for 

 much of the information I am able to give you to-night. 



[The author hero described the mode of setting fron) 

 diagrams, specially drawing attention to the fact that thg 



