Amongst the class of modern cannon, one of the most powerful is Krupp's seventy-one-ton gun. This, like all others of his make, is a breech-loader. Its dimensions are—length, thirty-two feet nine inches; diameter at breech end, five feet six inches; length of bore, twenty-eight feet seven inches; diameter of bore, 15.75 inches; diameter of powder-chamber, 17.32 inches. The internal tube is of two parts, exactly joined; and over this are four cylinders, shrunk on, and a ring round the breech. Its rifling has a uniform twist of one in forty-five. It cannot possibly be fired until the breech is perfectly closed. Its maximum charge is four hundred and eighty-five pounds of powder, and a chilled iron shell of seventeen hundred and eight pounds.