526 ON THE EXPLOSION OF THE BOILER 
been made, it is evident, that the result of this 
investigation can give only an approximate value 
of the pressure of the steam, in the boiler, which, 
when the pressure of the atmosphere is included, 
will be nearly 260 pounds on the square inch. 
—pt i 
When the term “ass was neglected, it was sup- 
osed, that e“’ was very small, when compared 
P bi Pp 
with unity ; and, it is found, that the supposition 
may be made, for e “=.061, nearly. 
It was stated, at the time of the inquest, that 
the Irk had been at work four years, and had run 
76860 miles. That there were two safety valves; 
one at the command of the engine-man, and the 
other placed beyond his control. On examination, 
after the accident, the former was found in work- 
ing order ; but, the spring-box was broken: the 
other was fast; but, this might have been the re- 
sult of a blow. 
It was stated by Mr. Joseph Clark, of No. 5, 
Elm Street, fitter, and repairer of Locomotives, 
that he had examined the rent in the fire-box; 
and, that it appeared as if there had been a flaw 
in the metal. 
