Mr. Chairman and Gentlemen:—I have read with great interest the discussions before the Institute in regard to the qualities of the steel which should be used for the fabrication of large guns for the Navy. I have heretofore written a letter to one of the members of the Institute, and, at the request of the Secretary, embody the opinions therein expressed in the following paper. My studies have led me to different conclusions from many of those expressed in Mr. Dorsey's paper before the Institute. The terms "mild " and "hard " steel do not of themselves convey a sufficiently definite distinction in the grades of steel. Mr. Dorsey, however, defines his use of the term “mild steel "as a metal " having a very low percentage of carbon, incapable of taking temper, etc., and having a tensile strength of from 55,000 to 65,000 pounds "; and of "hard steel" as having " a variable percentage of carbon, will take temper more or less hard, and having a tensile strength of over 90,000 pounds."
The Most Suitable Metal for Naval Guns
By Wm. J. McAlpine, Consulting Engineer ; Past President American. Society of Civil Engineers; Member of the Institution of Civil Engineers of London