58 Report of the Select Committee 
You cannot then state to the Committee how many instances 
of explosion you know of high pressure boilers ?—-No, I cannot. 
Are they more than in-low pressure boilers ?—i never heard 
of an explosion in the low pressure boiler of any consequence 
whatever, merely a giving way of the plates or the wearing out 
of the boilers; not such a bursting as can be called an explosion, 
May not every instance of explosion of the high pressure boilers 
with which you are acquainted, be traced to bad construction, 
er palpable mismanagement ?—I have never examined many of 
them, and therefore what they may be immediately traced to I 
do not know; but all the explosions I have heard of have been 
occasioned by the use of steam of high expansive force; the one 
I visited at Norwich certainly arose from the defective construc- 
tion of the boiler: it was extremely ill constructed. 
Was it not as well from the palpable mismanagement of the 
engineer?—That I do not know; we were told that it was; I 
have no doubt there had been very great temerity. and rashness. 
Was not that high pressure boiler which blew up in London 
the other day at a sugar-house, entirely owing to the most pal- 
pable misconstruction ?—I saw the boiler after it had burst ; and 
I certainly should not have made a boiler in that shape, to have 
withstood the pressure which it was intended to bear. 
Was not that boiler made of a different thickness ; one side 
of it three-quarters of an inch thick, and the other, side two 
inches thick ?—Those are very nearly the dimensions; but. in 
addition to that, there was a defect in ‘the casting, what we call 
a cold shut in the i iron. 
Is not the use of high pressure steam completely in its infaney? 
— Certainly, its introduction to general use is of much later date 
than the low pressure steam-engines. 
It is in fact to be considered as an invention of recent date?— 
It is. 
Have not material improvements taken place in the construc- 
tion and use of high pressure boilers, in consequence of the acci- 
dents which have happened ?—I conceive Woolf’s mode of con- 
structing boilers to be a considerable improvement ; a very ma- 
terial one I have likewise been told, though [ have never seen 
one, that Trevethick has invented ; a method of making boilers 
by increasing their length and decreasing their diameter, so as 
to render them capable of sustaining pressure to a much greater 
degree than heretofore. 
Have more accidents occurred since the invention of the high 
pressure boilers, than might have been expected from the inven- 
tion of any new system whateyer in the mechanical construction 
of engines ?—Perhaps not. j 
What 
