i^ 



No. 112.] 895 



To compare this iron with others, it is proper to assume bar 

 No. Ill as a standard, that having been hammered to a dull red 

 heat. The report already cited furnishes us with abundant data, 

 derived from experiments, made with the same machine, on other 

 kinds of bar iron in a similar state. Thus we have 



Strength in lbs. 

 per square inch* 



Iron from Salisbury, Conn., by a mean of 40 trials, 58 . 009 



Sweden, " '' 4 " .... 58.184 



Centre Co., Penn., ^« " 15 " ....58.400' 



Lancaster Co., " " " 2 " 58.6G1 



Mclntyre, Essex Co., N". Y., by a mean of 4 



trials, 58.912 



England, cable bolt (E. V.), by a mean of 



5 trials, 59.105 



Russia, by a mean of 5 trials, 76 . 069 



. Hence it appears, that the last only, is essentially superior to 

 the iron of Mclntyre. These are among the best varieties of bar iron 

 in point of tenacity. The fracture is of a light grey color, silky 

 lustre, and generally displays a compact structure. It is worthy 

 of remark, that most of the fractures took place in directions 

 oblique to the line of tension, and making with it, either in the 

 breadth or thickness, one or more angles of about 60 degrees each . 

 The fibrous structure of the metal was very marked in cutting 

 with the cold ciiisel, and was further developed by acids on part 

 of No. Ill, ou tlie surface of which delicate lines were shewn 

 traversing a distance of several inches. The specific gravity, in 

 an annealed state, it appears, was increased 1.2 per cent, by 

 hammer hardening. 



In conclusion, it may be observed, that as a large and increasing 

 demand for goud iron prevails in tlie United States, in proportion 

 to the increase of finished and accurate machinery, requiring 

 superior materials as wrll as workmanship, there can be no doubt 

 that any quantity whicli could probably be produced, if possess- 

 ing the properties of that above described, would command a 

 ready market and the best of prices." — Johnson^s Report. 



