Engraving depicting the casting of lead shots: this picture shows the inside of the top of the shot tower near Waterloo Bridge, London. Over a circular hole cut in a trap door a stand is placed containing an iron pan pierced with holes, the size depending on the shot to be made. Molten lead is poured through and the drops fall into water some 200 feet below. Arsenic was added to the lead to make the shot perfectly spherical, and to make it harder than if lead alone was used. Dated 19th century.