56 



REPORT — 1853. 



Table I. 



From the above, it is evident that the boiler which led to these experi- 

 ments could not have burst under a pressure of less than 300 to 350 lbs. 

 upon the square inch, as the failure of a single bolt in one of the cross- 

 bearers above the fire-box, under a pressure of 207 lbs. on the square inch, 

 was not the measure of its strength, but one of those accidental circum- 

 stances which is calculated to weaken, but not absolutely destroy its ultimate 

 powers of resistance. I have been led to this conclusion from the fact of 

 finding the upper part of the fire-box in every respect perfect. After the 

 removal of the pressure of 207 lbs. on the square inch, and comparing these 

 experiments with the appearance of the crown of the ruptured fire-box, I am 

 confirmed in the opinion that steam of high elastic force must have been 

 present to cause the disastrous explosion which eventually occurred. 



Again referring to Mr. Ramsbottom's Report, he states, — "That it has 

 been objected that the steam could not have been raised from 60 lbs. per 

 square inch, the pressure at which the safety-valve was blowing off before 

 being screwed down, to the pressure stated by Mr. Fairbairn in twenty- 

 five minutes ; but although I do not go all the way with Mr. Fairbairn as to 

 the strength of the boiler, I find, from experiments made upon a boiler of 

 somewhat similar dimensions, and placed as nearly as possible under the 

 same circumstances, that the steam was raised from 30 lbs. per square 

 inch to 80 lbs., as shown by Bourdon's steam-gauge according to the 

 following scale, namely, — 



