418 



REPORT — 1856. 



•will be proper to take the mean of the last three Tables as the breaking 

 weight at that temperature, 82,676 + 74.1 53 + 80.985 ^,^q^^^^j^^^ ^^^ ^^^^^^ 



3 

 inch= ultimate breaking weight at 212°. 



Table XXIV. — Sectional area =-19635. , 



Here again, in the above experiment, is a perceptible increase of strength, 

 as the temperature rises 38°, from 79,271 to 82,174 lbs. per square inch, and 

 30 in the next Table, where the increase is still greater. 



Table XXV — Sectional area =-24850. 



The increase of 20° of temperature in this experiment gives a correspond- 

 ing increase of strength of 3882 lbs. per square inch, something more than 

 the increase exhibited in the previous experiment. There is, however, a 

 remarkable coincidence in the ratio of the strengths as they rise with the 

 increase of temperature, the only exceptions being those of Tables I. and 

 XXII., but in both cases the anomaly is sufficiently explained by the state of 

 the fracture. 



Table XXVI.— Sectional area =-19635. 



In this experiment it will be observed that there is a falling off in tenacity 

 with the increase of temperature from 86,056 to 80,570 lbs. per square 

 inch. It is difficult to account for this discrepancy, as the fracture in this, 

 as in the previous and succeeding experiments, appeared sound and free 

 from flaws of any description. 



