* The samples here given are arranged in the order of ultimate strength. The table illustrates the great com- 

 plexity of the problem of determininc; the eflect of any given substance on the physical properties. It will be noticed 

 that the specimens containing moderately large amounts of copper are low in ductility, — that high carbon or high sum 

 of carbon and manganese generally gives high strength. The first specimen seems to indicate a weakening effect 

 of silicon when a moderate amount of carbon is present. It has to be remembered that no table of this kind proves 

 much unless nearly the same amount of work has been spent on the different specimens in the process of manufnclure. 

 Most of the lines give averages of a numb.-r of tests of similar steels. The table has been largely compiled from the 

 Report of the Board on Testing Iron and Steel, Washington, 1881, and from results quoted in Howe s ' ISIetallurgy 



of Steel." , , , , . , J • A 



t The strengths and elasticitv data here given refer to bar or plate of moderate thickness, and are in jiounds per 

 square inch. Mild steel wire generally ranges in strength between looooo and 200000 pounds per square inch, with 

 an elongation of from 8 to 4 per cent. Thoroughly annealed wire does not differ greatly in strength from the data 

 given in the table unless it has been subjected to special treatment for the purpose of producing high density and 

 fine-grained structure. Drawing or stretching and subsequent rest tend to increase the Young's Modulus. 



SMiTHSONiArt Tables. 



71 



