on Steam-Boats. 335 
Do you at all know, whether there is any difference between 
the power of the steam or water to scald, when under high or 
low pressure ?—The steam from low pressure sealds much worse 
than the steam from high pressure ;. as to the water, I cannot 
say. ! cannot conceive that water can issue to any great di- 
stance from a high pressure boiler, it must svon be steam; it 
must be converted into steam from its heat; water cannot go 
beyond 212 degrees of heat, unless it is confined; beyond that 
it must be steam. : 
Have you ever known any person scalded by the steam or the 
water issuing from a high pressure boiler ?—No. 
Have you ever known any instances of persons being scalded 
by the steam or water from a low pressure one, besides that 
which you have mentioned ?—I have heard of a great number 
of instances of this in different mines, but only that one came 
directly under my own eye. 
You have given the Committee to understand, that when 
boilers made of wrought iron are exposed to steam of high. pres- 
sure there is great difficulty in making them sufficiently strong, 
for that the rivets are apt to draw, and the joints to become 
loose ; do you not conceive it very possible for the boilers in such 
cases to become useless by permitting the steam to escape, and 
yet not to explode so as to produce any fatal accident whatever? 
—I am quite of opinion, that boilers made of wrought iron for 
high pressure engines will soon become leaky, and may not ex- 
plode. I have known of an instance of a boiler of that deserip- 
tion made for Herland mine, and ‘it soon became leaky, and un- 
fit for use in a very short time; the consequence of which is, 
the mine is knocked up, and a great number of people out of 
employ. 
But no accident happened in consequence of this, by which 
any person was injured >—No. 
Supposing the only object to be safety to the lives or limbs of 
the persons who should be surrounding the engine, would you in 
that case prefer having the boiler of a high pressure engine of 
wrought or of cast iron ?—I would have cast iron, because it can 
certainly be made stronger than wrought iron for the same ex~ 
pense. 
Do you take into that calculation the difference of the mis- 
chief which might be occasioned, supposing the boiler by any 
accident to explode ?-—I consider that risk is so small as that it 
scarcely need be taken into the question, because all explosions 
may be easily prevented by proving the boiler every time it is 
cleansed, which I think should be at least every month, 
Is the operation of proving the boiler so easy as that it may 
be performed on board a steam-boat every month without ex- 
pense 
