This opening, which may properly be called the mouth, varies in the smaller sizes from 2 or 3 in., in the laboratory crusher, up to from 30 by 12 in. to 30 by 18 in. in the Monarch, and to 24 by 24 in. in a still larger and exceptional size, specially made by the inventor for the Calumet & Hecla Co., Lake Superior, which takes in masses of ...