I am trying to figure out what some lead bars were used for. The bars are aproximately 9 inches long, 3/4 inches wide and 1/4 inch thick. They have markings on them that read: SC CORNELL N YORK. Near the end of the bar is a 1/4 inch hole next to the K in York. This item was found at an 1800's era shipwreck dive site. What would these be used for and what do the markings mean?