No. 50.] 
307 
The foregoing trials having, as it was conceived, fully established 
the freedom of this iron from the defects known either as hot shortness 
or cold shortness, and its softness and malleability being amply tested 
by the cutting and hammering incident to these experiments, the next 
step was to determine the absolute force of cohesion, together with the 
extensibility, when subjected to longitudinal strain, and the interior 
structure of the metal under various circumstances, including that of 
welding in the ordinary way. 
For this purpose five bars were drawn out and prepared from the 
specimens already described, numbered I, II, III, IV, and V, each 
about 9 or 10 inches long, 1 inch wide and .2 inch thick. 
No. I. after being reduced to a nearly uniform size throughout its 
length, was annealed at a red heat and allowed to cool slowly in the 
air. 
No. II. was hammer hardened, or beaten with moderate force, 
throughout its length until it had been for several minutes black, the 
hammer being occasionally moistened during the process. 
No. III. was forged out and hammered till it was only visibly red 
in daylight, being left at about the temperature at which workmen 
cease their operations on many of the articles which they produce. 
No. IV. after being brought to an uniform size, was upset for about * 
3 inches, in the middle, and was then annealed and cooled slowly. 
No. V. was drawn out, cut into in the middle, and welded together. 
This sample was only 6j inches long. 
All these bars were then carefully gauged, both in breadth and thick- 
ness, at every inch of their lengths, before commencing the trials of 
tenacity. The machine employed in testing them was the same which 
had been used in experiments made at the request of the Treasury De- 
partment, on the strength of materials for steam boilers, for a descrip- 
tion of which the reader may be referred to the report on that subject.* 
The following table will be understood without any other remark than 
that the bi caking weights in the 5th column, are corrected for friction 
of the machine. The specific gravities of several of the fragments of 
each bar after it had been broken up, are given under the head of ob- 
* See also Journal of the Franklin Institute, vol. xix. p. 84, 
