| Show how to tell iron from steel A writer in the glasgow engineer in pointing out some of the most practicable data in testing iron and steel lays down a simple rule to start with namely that in any case chero a fracture of iron gives long silky fibers of a leaden arfe the fibers cohering and twisting together before breaking it may be considered a tough soft iron further a medium even grain mixed with fibers ia a good sign while a short and blackish fiber indicates badly refined iron a very fine grain also denoting a bard and steely iron which is apt to be cold short and hard to work with the file again coarse grain with a brilliant crystallized fracture and yellow or brown spots denotes a brittle iron cold short working easily when heated and welding well nitric acid will produce a black spot on deteel the darker the spot the harder the steel while iron on the contrary remains bright if touched with that acid good deteel 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 deteel will bear a white heat without falling to pieces and will crumble under the hammer at a bright heat while at a middling heat it may be drawn out under the hammer to a fine point |
