ON THE STRENGTH OF LOCOMOTIVE BOILERS. 



57 



uch. 



These experiments, although perfectly satisfactory as regards the time 

 required to raise the steam (under ordinary circumstances of the engine, 

 standing with the fire lighted, and the usual quantity of coke in the furnace) 

 from 30 up to 80 lbs. on the square inch — it was nevertheless considered 

 desirable to repeat them through a still higher scale of pressure and tempe- 

 rature, and to ascertain, not only the exact time, but the ratio of increase, 

 and the corresponding temperature of the steam in the boiler as the pressure 

 progressively increased. For these objects, two delicately constructed ther- 

 mometers were prepared by Mr. Dalgetti, and having adjusted Bourdon's 

 pressure-gauge by a corresponding column of mercury, and an engine having 

 been placed at my disposal, the following results were obtained : — 



Experiment made May 1th, 1 853, to determine the rate of Increased Pressure, 

 Temperature of Steam, S^c. in a Locomotive Engine with the Safety-valve 

 screwed down and the Fire under the Boiler. 



Table II. 



