[No title]
... DURATION OF MALLEABLE IRON RAILS.—Time was when engineers generally were under the impression that rolled IIIIn edge rails, of 50 lbs. to the yard, would last from forty to sixty years, but experience is fast dissipating all such notion*, demonstrating that the duration of rails of malleable iron not determined by some superficial wear, but by the time which M reqoirea for a given amount of ...