100 Report of the Select Committee on Steam-Boats. 
nerally used in the condensing-engine?—-From two and a half to 
four pounds, 
_ Do you not apprehend that the strength of the boileris cal- 
al upon what may be required to resist that low pressure ?—= 
es, 
Is it not extremely possible, in the common use of a condensing 
engine, that by accident, or the inattention of the engineer, the 
pressure may be increased very much beyond that which you 
have just mentioned ?—No inattention would produce it while 
these securities exist; because the water would be discharged 
through the feed-pipe, and the mischief prevented. 
Did you ever know the steam-pipe used in any condensing= 
engine on board a steam-boat ?—I fancy they never are. 
Did you not hear that the Norwich boiler was blown up by 
the very fact of the inattention or temerity of the engineer ?—I 
did hear that. 
Is not that inattention or temerity equally to be applied toa 
condensing as to a high pressure engine ?—The engineer may tie 
down the valve occasionally; it is very natural to expect it in 
steam-boats. I fancy it is too frequently done; there are in- 
stances where something of that sort was said in conversation at 
Norwich, that where a man waited for passengers, and wanted 
to get up with the other boats, he did it. 
Could a mercurial syphon be applied to a boiler, so that it 
would meet the observation of all the passengers on board the 
boat ?>—I should think it could; but the discharge of mercury, 
in case of explosion, might produce very serious effects. 
If the syphon was of a sufficient bore, it would be the means 
of preventing the effects you have spoken of ?>—No doubt. 
In order to give security to the public in travelling by steam- 
boats, do not you think that it might be necessary to have an 
examination of each engine two or three times in a year?—Cer- 
tainly; once every six months. I think it would create confi- 
dence, and that is a great object. 
And that is your opinion, whether the boiler is constructed of 
cast iron or wrought metal ?—Yes. 
You think that without this examination a condensing-engine 
would be unsafe ?—I think it would be advantageous to have an 
examination. 
In your judgement, would an inspection of the boilers of a 
steam-engine, of a condensing-engine, and a high pressure en- 
gine, be equally necessary, with a view to give security against 
accidents by explosion ?—Yes ; both. 
Do you think any danger to lives is to be apprehended from 
condensing-engines without examination ?—I do not think any 
material danger would arise. “ 
[To be continued.] XIII, Further 
