386 Report of the Select Committee on Sleam- Boats. 
pense or inconvenience ?-—Certainly; it consists, as J have said 
before, only in filling the boiler with cold water, putting great 
additional weight upon the safety-valves, and then injeeting wa- 
ter by a forcing pump till the valve is lifted with the additional 
weight. 
Is it then your opinion, that every steam-engine ought to be 
provided with those means of proving the boiler, and that they 
ought to be applied as often as yon have mentioned }—Yes, they 
should; the very pump by which the boiler is supplied with wa- 
ter may be used conveniently and sufficiently for this purpose ; 
high pressure boilers are all fed in the common way by foreing- 
pumps, and there is no difficulty in applying it to the low pres- 
sure boilers. 
Have you found the use of a high pressure engine of any ad- 
vantage to the Cornish mines ?—Of very great advantage, which 
ean be proved by locking at the monthly reports, which I am 
fully convinced are correct. 
Do you conceive that a low pressure engine can be reckoned 
entirely safe, unless furnished with the safety-valves, such as be- 
fore described, and to one of which at least the engine-man has 
no access '—I conceive that every engine ought to have those 
valves ; and one should be locked up’to prevent careless engine- 
men doing mischief, which low pressure engines are as liable to 
as high. 
Have you any means of estimating the comparative consump- 
tion of coals by either high or low pressure engines ?—Yes. 
Be so good as to state your opinion upon that point ?>—I con- 
ceive that a high pressure engine does greater duty with the 
same coals than a low, which will also be proved by the monthly 
reports. 
Have you any further information on this subject, which you 
wish to communicate to the Committee ?—Being desired to 
attend here on the part of the proprietors of three of the largest 
mines in Cornwall, the united mines of Crowan, Dolcoath and 
Wheal Unity, I wish to state their hope, that the Legislature wilt 
not interfere to prevent the use of high Pressure engines, either 
on board boats or in any other way. | ; 
You have not been used to steam-engines on board hoats, but - 
in mines chiefly ?—Chiefly in mines. [ have s seen them on board 
boats, , 
Do your answers apply equally to steam-engines on Scie 
boats as in mines, or may not more caution bé necessary in boats 
than in mines?—I conceive the answers to be applicable to, 
boats as well as to mines. oe Tew oe : 
LIV. ‘On 
