96 Experiments on tioo varieties of Iron. 



part where the breadth was 1.295 inches, and the thickness .59 

 inch. This bend was made flatwise, and continued until the cor- 

 responding faces on the inside at about one inch from the middle 

 of the inner curve, were .4 of an inch apart, and the widest part 

 of the opening only .45 of an inch. 



The aUeration in the form of the bar appeared to be hmited to 

 this portion. On measuring along the interior and exterior edges 

 of this curved part, the former was found to be 2.15, and the lat- 

 ter 3.S inches, manifesting a difference in the length of the inner 

 and outer fibres of 1.65 inches in about 2^ the original length of 

 the bent portion. 



By this kind of trial, the whole form of the cross section of 

 a bar is changed, and, instead of straight lines, exhibits only 

 curves. In the present case, the parallelogram. Fig. 1, was con- 

 verted into the form of the curved Fig. 2, the largest curve be- 

 ing on the inside of the bend. This change of figure and dis- 

 placement of parts, was borne without exhibiting any signs of 

 rupture, until the degree of curvature above stated had been at- 

 tained, when a few cracks began to appear on the exterior part 

 of the bend. 



Fig. 1. Fig. 2. 



The next test to which this iron was subjected, was to heat a 

 portion of the bar to redness, quench it in cold water, and then 

 bend the same portion cold, in the manner already described. 

 No difference of result was obtained, except a greater facihty in 

 producing it. A few slight surface cracks were seen near the 

 close of the operation. 



A third trial of a similar kind on a bar annealed and cooled in 

 dry ashes, resulted like the preceding, but exhibited rather more 

 cracks on the exterior surface of the bend, than either of the fore- 

 going. 



Another trial of the toughness of this iron when cold, was 

 made by drawing out a bar .7 of an inch wide, .18 inch thick, 

 and 5.4 inches long, and twisting it cold, in the manner of a 



