219 
sphere. It was the property of a sphere to fit a circle in all 
directions. In order to secure the perfect freedom of the 
valve at all times, per se, and without the necessity for the 
engineman experimenting upon it, he had resorted to a 
very simple expedient, by contriving that the wave-like 
action going on in the water should communicate a slightly 
pendulous motion to the valve, sufficient to prevent its being 
fixed in its seat. He would do away with the system of 
leverage, and have a direct weight attached to the valve, 
and placed inside the boiler, so that the engineman would 
be unable to tamper with it. This valve possessed another 
recommendation — that of cheapness, at it could be made for 
less than the ordinary cost. 
Several gentlemen spoke in high terms of approbation of 
Mr. Nasmyth's safety valve, considering it the most simple 
and efficient which had come under their notice. A case 
was mentioned in which the ordinary safety valve, although 
tried every day, acquired a considerable amount of friction, 
and several cases were referred to in which it had been 
tampered with by reckless enginemen. On board a steamer 
the valve had been tied down, and in another case a man 
was found to be hanging at the end of the lever ! In the 
case of an accident for which the man was sent to take 
his trial at York, the spindle was found to be bent, but 
whether this occurred before or after the explosion, could 
not be ascertained. Hence the importance of the safety 
valve being out of the reach of the person having the 
control of the engine. 
Mr. West stated that when travelling on a locomotive, 
if they were behind time, he found that the engineman 
almost invariably held on to the safety valve, knowing that 
very little risk was incurred, and that lost time must be 
made up. He mentioned another case, as showing how 
precautions, apparently the most effective, may be defeated 
