on the Explosion of Steam- Boilers. 405, 



process of rolling it. Mr. Taylor admits that in theory these 

 angular parts are bad ; but he goes on to say, that " it does 

 not appear in practice that these have been the first to give 

 way." Whether they are the first parts to give way, I cannot 

 pretend to say ; it is enough for me to know that they have 

 eventually given way, and that it is to the failure of these parts 

 that the tremendous effects related by Mr. Taylor are to be 

 attributed. It is not at the junction of the angle iron to the 

 outer case where I should apprehend the greatest danger, be- 

 cause the outer case is not liable to a change of form. I ap- 

 prehend more danger from those parts where the inner tube 

 joins on to the front ; because, as I shall presently show, the 

 inner tube is extremely liable to a change of form ; and ac- 

 cordingly it is here where a fracture is exhibited in all the in- 

 stances above alluded to. 



I consider the introduction of a tube within a high-pressure 

 boiler to be bad under any circumstances, but it is peculiarly 

 so where the furnace is placed in it. If these boilers had 

 their fire-places underneath, as shown in Mr. Taylor's second 

 sketch, and the tube used only as a return flue, some of my 

 objections would be removed, and I conceive a better effect 

 would be produced : a larger surface would be exposed to 

 the direct action of the fire, and there would be as much 

 heating surface generally. The fire-place and ash-pit could 

 then be made of any size required ; the latter of which is by 

 necessity most objectionably small where the furnace is inside 

 the boiler. This is an evil of some jnagnitude, both as re- 

 gards the draught, as well as the wear and tear of fire-bars. 

 Lastly, but not tlie least important consideration in a tube- 

 boiler, the water would be equally heated throughout. 



The objections raised by Mr. Tayloi-'s Cornish agents to a 

 brick furnace would of course apply to this mode of setting a 

 tube-boiler, as well as to the use of a plain cylinder where the 

 furnace is by necessity of bi'ick. I confess the adhering of 

 clinkers to the sides of a brick furnace to such an extent as to 

 injure the draught, to be perfectly new to me; and as Mr. 

 Taylor does not state this of his own knowledge, he must ex- 

 cuse me for doubting the fact. 



Having stated under what circumstances the tube-boilers 

 may be rendered less objectionable, I shall proceed to consi- 

 der them as they are at preseiit used in Cornwall, and point 

 out what I take to be the defects, as relates to their liability to 

 accident. 



In the first place, I consider the want of space in the boiler 

 over the fire-place a serious evil. If loo uuich of (his space 

 be occupied by water, then there Is not room enough left for 



steam ; 



