No. 50.] 
305 
SECTION XXXIV. 
Extract from a report, hy Prof. W. R. Johnson, of Experiments 
on the iron, manufactured at the village of Mclntyre, Essex county, 
NeiV'York. 
To ascertain the toughness and ductility of this iron when cold, I 
caused the bar to be bent at a temperature of 50° at a part where the 
breadth was 1 . 295 inches, and the thick- 
ness .59 inch. This bend was made flat- 
wise, and continued until the correspond- 
ing faces on the inside, about one inch from 
the middle of the inner curve, were four- 
tenths of an inch apart, and the widest part 
of the opening only .45 of an inch. The 
alteration in the form of the bar appeared 
to be limited to this portion. On measur- 
ing along the interior and exterior edges of 
this curve, the former was found to be 
2.15, and the latter 3.8 inches, manifesting a difference in the length 
of the inner and outer fibres of 1 .65 inches in a length of about 2j, 
the original extent of the bent portion. See Fig. 1. 
By this 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. 2, was converted into the form of Fig. 3, the 
largest curve being on the inside of the bend. 
Fig. 2. 
Fig. 3. 
1 0 8 3 ... 
/■5I 
This change of figure and displacement of parts were borne without 
exhibiting any signs of rupture until the curvature above stated, had 
been attained, when a few cracks began to appear on the exterior part 
of the curve. 
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 
[Assembly, No. 50.] 39 
