involved in the Construction of Artillery. 389 



" II. — Metal from the gun, annealed, but not hammered: — 



lbs. 

 First specimen, from position marked h, lengthwise of fibre of shaft, made 



of longitudinal bars, broke in two places, the first breaking- weight being, 36,300 



And the second breaking-weight, 39,100 



Second specimen, from same place, • . 32,800 



" III. — Metal from the gun, drawn down, at a welding heat, under forging- 

 hammer : — 



First specimen, from the position marked m 58,000 



Second specimen, from the same 68,950 



" Recapitulation : — 



1 . The average tensile force with which the specimens from the interior of 



the gun broke, when strained in the direction of the fibre, is less than 32,100 



2. The specimen from the interior, strained in a direction across the fibre, 



gave • 23,700 



3. The specimens from the outside of the gun, across the fibre, gave an 



average of less than 45,333 



4. Annealed specimens from the interior, strained lengthwise of the fibre, 



gave an average of, 36,067 



5. The average of all the specimens from the gun, not hammered, is . . 33,300 



6. The average of the specimens worked down under the hammer is, . . 63,475 

 " The general conclusions from these results are the same as those from the experi- 

 ments made by the member of the Committee in Boston, so far as the two series can be 

 compared. 



lbs. 



1. The average strength of the iron, as it existed in the gun, from both 



series, is 33,586 



2. The average strength of the iron from the gun, after being drawn down 



with the hammer, from both series, is 59,824 



3. The average strength of the original bars, from the experiments of the 



first series, is 46,950 



4. The average strength of good American iron, from the investigation of 



a former Committee of the Institute, is 60,000 



" No experiments were made, at the Hall of the Institute, on the original bars of which 

 the gun was formed, owing to a misapprehension, by Messrs. Ward and Co., of the request 

 of the Committee (see Question 7, and its answer) ; none of the metal, in its original state, 

 was sent to Philadelphia. The conclusion, therefore, in reference to the quality of the 

 original bars, rests on the experiments made in Boston. In the accuracy of these experi- 

 VOL. XXIII. 3 E 



