ESSEX COUNTY. 257 



after annealing tlie bar, and cooling it off in dry ashes. In attempting to carry llic torsion 

 beyond this extent, the bar was twisted olY at the jaws of the vice, in which the operation was 

 performed. 



Having thus proved that this iron is not under any circumstances cold short, I caused the 

 bar 1 1 inches wide, and ' 6 inch thick, to be heated to a fair working red heat, and in that 

 state bent flatwise over the corner of an anvil, and a right angle exterior and interior to be 

 formed \ of an inch from the end. The exterior angle remained perfectly sound. On the 

 interior, a thin scale only of metal appeared to be corrugated and partly detached from the rest 

 of the mass, owing, probably, to a defect in welding ; but not the least sign of a tendency to 

 fracture was discovered. Another portion of the same bar was heated as before, and tlu'ee 

 inches of it bent over and hammered flat upon the face of the adjacent part. 



Complaints are made by workmen, that much of the iron which they employ will not sus- 

 tain either of the two preceding operations. They were, however, borne by the iron under 

 trial, without evincing any weakness or undue distortion of parts. 



A third test of the quality of this iron, when hot, was afforded by heating about three inches 

 near the end of the bar, and driving a steel punch 0"8 of an inch in diameter, quite through 

 it. This was done without splitting or cracking at the edges, as is too often the case in making 

 screw-nuts. Machinists are well aware of the importance of a good material for the forma- 

 tion of screws and nuts. 



The forcgoins 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 mallea- 

 bility 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 circum- 

 stances, 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 

 0*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 tliey produce. 

 No. IV., after being brought to an uniform size, was upset for about tlu-ee inches in the middle, and was 



then annealed and cooled slowly. 

 No. V. was dra\vn out, cut in two in the middle, and welded together : this sample was only 6^ inches 



long. 

 Geol. 2d Dist. 33 



