98 Report of the Select Committee 
Could not a boiler then be made for what they call a high 
pressure engine, equally safe?—I should apprehend not, for the 
reasons I have stated: I have made several boilers, and I find if 
the plates are thick beyond the dimension usually employed for 
condensing-engives, that they do not prove equally steam-tight. 
Explain whether you mean the plates or the seams >—I mean 
that the seams are not equally steam-tight. 
Did you from any report you heard, besides the bad construc- 
tion of the boiler at Norwich, discover that any negligence was 
imputable to the direction of that engine ?—It was presumed by 
report that he was imprudent frequently; for the purpose of im- 
pelling his vessel with greater force, that he did load his engine 
too much. 
Did you sée any body who had escaped from that accident 
who was on board the boat ?—I did not. 
If there was too much weight added to the valve, would not 
that occasion the explosion ?—There is no doubt that was the 
case; but a much smaller degree of pressure would have burst 
-a boiler so constructed. 
Then if a boiler had been made properly, and a man had been 
so imprudent as to have loaded the safety-valve, the same acci- 
dent might have occurred ?—-Certainly. 
You have said, from the power that was wanted with regard 
to steam-boats, you thought condensing-engines were the best 
engines applicable for that purpose ?—I think so, no doubt. 
Do you mean the best as applied only to safety, or for use >— 
For safety onlv. 
But if a high pressure engine could be made with equal se- 
curity, would not that be more convenient to be used on board a 
boat than a condensing-engine ?—It would take less room. 
Would not it in many cases, as they are now constructed, con- 
sume less fuel in proportion to the power ?—I am not acquainted 
with that fact; but T have frequently asked, and I find in the 
common high pressure engine there is no saving in the fuel, but 
they are cheaper and more simple in their construction. 
Do you apply that to the high pressure engine which they call 
the Trevethick engine ?—Yes. 
Not to any other ?—Not to Woolf’s. 
Nor to Simms’s ?—I have never seen either one or the other. 
Suppose that a high pressure engine was to be used in a boat, 
what construction of boiler or safety-valve applied to that boiler 
should you advise, in order to give it the greatest possible ser 
curity ?—I really am unable to answer that question satisfactorily ; 
ofcourse the more safety-valves there are employed, the greater 
security there will be against the chance of explosion; I believe 
that the principal source of the explosion of high pressure en- 
gine 
