258 
GEOLOGY OF THE SECOND DISTRICT. 
All these bars were then carefully gauged, both in breadth and thickness, 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 
Department, on the strength of materials for steam boilers, for a description 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 breaking weights in the fifth 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 observations, and may serve as well to 
illustrate the general character of the iron in this respect, as to indicate the effect of the several 
methods of preparation on the density of iron. 
The following experiments confirm the evidence already adduced of the great toughness and 
ductility of this variety of iron. Besides the facts mentioned under the head of observations 
in the seventh column, we may add, that after the first fracture on each bar, a measurement 
was taken between two of the inch marks still remaining on one of its parts, and the following 
results obtained, viz: 
No. I. In an original length of 6 inches, had been elongated 0 *87 inches = 14 *5 per cent. 
II. .. .. 4 “ . 0-2 “ = 1*5 “ 
III . 5 “ . 0-6 “ = 12-0 “ 
IV . 4 “ . 0*2 “ = 5-0 “ 
See also Journal of the Franklin Institute, Vol. 19, p. 84. 
