DescriptionBeginner's slide rule, model 4058C (Mannheim type), 10 inch, made by Keuffel & Esser Co.in Hoboken, no date, circa 1925-1941. Black printing on boxwood, frameless glass cursor with wood slide blocks (four screws; do not go through back of wood.) This item was not issued with a serial number. With: two piece storage slipcase; paper covered; lettered in dull gilt. No instruction book or sheet present. Printed on back: Beginner's Slide Rule. 4058 C. Keuffel & Esser Co., N.Y. (manufacturing for K & E was in Hoboken from 1875 to the late 1960s.) Back has printed chart of Equivalents and Abbreviations from U.S. Bureau of Standards Circular No. 47 (first published in 1914, but not used by K & E until the 1920s.) Note: the model name and number on the back is centered at the top. Chart source and company name is to the left. Note the B,C scales on front; back has celluloid window with S, L, T scales. The style of the slipcase and cursor suggests the date of manufacture was nearer the early date than late date.