Keuffel & Esser 1742 Fuller's Spiral Cylindrical Slide Rule

This rule consists of an outer wooden cylinder that both slides up and down and rotates. Two brass rings lined with felt are inside this cylinder. The cylinder is covered with paper marked with a single spiral logarithmic scale graduated into 7,250 parts and having a length, according to the maker, of 500 inches (nearly 42 feet). Inside the outer cylinder is a longer wooden cylinder, covered with paper marked with decimal, conversion, and sine tables, and half-lined with felt. A solid mahogany handle is at one end. A brass index is screwed to the top of the handle. A second, longer brass index is screwed to the mahogany base and marked with a scale of equal parts used in finding logarithms. A third and removable brass cylinder is inside the instrument and attached to the base.

The tables on the middle cylinder include: decimal equivalents of feet and inches in feet; decimal equivalents of quarter weights and pounds in hundredweights; decimal equivalents of ounces and pounds in fractions of a pound; decimal equivalents of pounds, shillings, and pence in fractions of a pound; decimal equivalents of pence in shillings; days of the year as a fraction of the year; decimal equivalents of subunits of an acre; properties of various metals and woods; decimal equivalents of minutes of a degree in degrees; the Birmingham wire gauge; various conversion factors (mostly for weights and measures); and natural sines.

The outer, sliding cylinder is marked near the top: FULLERS SPIRAL SLIDE RULE. Near the bottom is marked: ENTD. STATS. HALL; STANLEY, Maker, LONDON. The bottom of the outer cylinder and the top of the long brass index are stamped: 858. According to Wayne Feely, the serial number 858 dates this instrument to 1895 or 1896.

The rule is in a rectangular mahogany case marked in script on the top: Calculator. A paper Keuffel & Esser label on the inside lid of the instrument's mahogany case is marked in ink: 1742 (/) Fuller's (/) Spiral (/) Slide Rule. Fuller's Spiral Slide Rule was first listed in Keuffel & Esser's 1895 catalog and sold for $28.00.

George Fuller, professor of civil engineering at Queen's University in Belfast, Ireland, patented this instrument in 1878. The Stanley firm made about 14,000 Fuller's spiral slide rules over nearly one hundred years, with K&E distributing a large share of the instruments sold in the United States. The Naval Engineering Division of the U.S. Coast Guard transferred this example to the Smithsonian in 1959. The Coast Guard engineers provided brief instructions:

"To calculate (5 X 6 X 4)/3 turn the outer cylinder until the first factor (5) is opposite the fixed pointer, set the slot in the movable indicator to read (0), turn the outer cylinder until the second factor (6) appears opposite the movable indicator. (The result will be found on the outer cylinder opposite the first indicator.) To multiply by the third factor (4), set the slot in the movable indicator to (0), turn the outer cylinder until the movable indicator indicates the third factor (4); (the result will be found opposite the fixed indicator.) To divide by (3) set the movable indicator to (3), turn outer cylinder until the slot in the movable indicator is (0) on the outer cylinder and the result will be found opposite the fixed pointer."

See also MA.311958, 1998.0046.01, and MA.313751.

References: William Ford Stanley, Surveying and Leveling Instruments, 3rd ed. (London, 1901), 542–543; Wayne E. Feely, "The Fuller Spiral Scale Slide Rule," Chronicle of the Early American Industries Association 50, no. 3 (1997): 93–98; Catalogue of Keuffel & Esser (New York, 1895), 190.

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