Show HT to ten iron from A writer in the glasgow engineer ic pointing out somo of the most practice cle data in testing iron and steel lay down a simple rule to start with namely that in any case where a fracture of iron gives long silky fibers of a leaden hue the fibers cohering and twisting together before it may be considered a tough soft iron further a medium even grain mixed with fibers is a good sign while a short and blackish fiber indicate badly refined iron a very fine grain also denoting a hard and ethely iron which is apt to be cold short and hard to ork with the file again coarse grain a brilliant crystallized fracture and yellow or brown spots denotes a brittle iron cold short worling easily when heated and welding well nitric acid will produce a black un steel the darker the spot the harde the steel while iron on the contrary remains bright if touched with that acid good steel in its soft state has a curved fracture and a uniform gray lustre but in its hard state a dull silvery uniform white again good steel will bear a white heat without falling to pieces and will crumble under the hammer at a bright heat at a middling heat it may be drawn ouk tinder the hammer t line point |