AMERICAN INSTITUTE. 573 



I think I hear you inquire for some evidence of the truth or 

 plausibility of my theory; I avei that this establishes it : lead low 

 temperature steam through a pipe into a bucket of cold water, 

 the latter will be dispersed throughout the room. Wait for high 

 temperature steam, and repeat the experiment. No water will be 

 seen, for the excess of temperature has converted it instantane- 

 ously to vapor. This experiment appears to me conclusive, in- 

 asmuch that it is contrary to the assumption that an Increase of 

 pressure should simply have expelled the water with more force. 



The prudent engineer will regard a thermometer as an indis- 

 pensable appendage to a boiler, will see that his safety valve is in 

 perfect order, and, on no account, attempt to restrain the steam 

 if undue temperature is shown. Explosions do and will take 

 place, even whilst the steam issues from tlie safety-valve, never- 

 theless threatened ones may be preyented by close observation 

 and precautionary measures adopted on fair warning. 



I have given you my ideas upon the thesis suggested, and 

 leave you to incite opposition thereto in any way you may think 

 proper. Truth will be elicited or confirmed through discussion, 

 enlightened by experimental observation. 



Very sincerely your friend, 



B. p. WRIGHT. 



Mr. John D. Ward, of Jersey City— Asthe idea is held, and 

 taught by many, that a steam boiler cannot explode so long as it 

 is supplied with the quantity of water required to keep all parts 

 covered therewith which are exposed to the direct action of the 

 fire, so that no part can become unduly heated, the writer begs 

 leave to offer some remarks respecting explosions generally, and 

 inquire whether the above stated opinion is really well founded, 

 or warranted by the ordinary condition of things as they appear 

 in a steam boiler while at work. It appears to be taken for 

 granted by the advocates of this opinion, that explosions of steam 

 boilers have generally, if not always, been preceded by a defi- 

 ciency of water; in consequence of which some portion of the 

 metal has been highly heated and of course weakened, which 

 weakening was the immediate cause of disruption at the over- 

 heated part, with the pressure previously existing; or, that while 

 in that state the part has been suddenly covered with water, and 

 that instantly converted into steam to such an extent, as when 

 combined with that previously formed its force becomes irresist- 

 ible. That an explosion may occur under the circumstances 

 first mentioned, is probable, especially if the heating should be 



