Slide RulesCylindrical Slide Rules
Writing a logarithmic scale in a spiral that is then imprinted around the outside of a cylinder allows instrument makers to lengthen the scale. Since a logarithmic scale only needs to run to 10 twice to include all possible results from adding or subtracting two logarithmic numbers, this means that the distance between the points on the scale may be increased. When any two numbers on the scale are further apart, the user may read a fractional position between these numbers (expressed as a decimal) to a finer level of granularity. For example, on a 10" linear slide rule, results generally may be calculated to only three significant figures (0.123, 1.23, 12.3, 123, 1230, and so on). A cylindrical slide rule may provide results of up to seven significant digits (0.1234567, 1.234567, 12.34567, 123.4567, 1234.567, and so on).
On the other hand, cylindrical slide rules were typically about twice as expensive to produce as linear slide rules, and the provenances for the objects on this page indeed suggest that, in the main, only corporate and government offices could afford them. A number of the objects in this category were received with instruction manuals and advertising pamphlets, which may be viewed in the Index by Makers & Retailers. The collection includes multiple examples for several of the objects, as the 23 items below represent only eight different slide rules, half developed in Europe and half invented by Americans. The cylindrical slide rule by Edwin Thacher, a Pennsylvania railroad bridge designer, also illustrates the 19th-century shift in production from Europe to the United States, as originally William Ford Stanley's London firm made the entire instrument. Then, Keuffel and Esser of New York City began constructing the wooden drum and brass and wood stand while continuing to import the scales printed on paper and pasted around the drum. Finally, K&E developed its own dividing engine for printing the scales and henceforth manufactured the entire instrument in the United States.
"Slide Rules - Cylindrical Slide Rules" showing 1 items.
- This rule consists of an outer wooden cylinder that 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 7250 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. A solid mahogany handle is at one end. A third cylinder of brass is inside the instrument. 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.
- 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 is stamped: 1099. The top of the long brass index is engraved: 1099 (/) 98. According to Wayne Feely, these numbers indicate the instrument has serial number 1099 and was made in 1898.
- The rule is in a rectangular mahogany case marked in script on the top: Calculator. A blue sticker attached to the inside lid of the case reads: DRAWING MATERIAL (/) FRED. A. SCHMIDT. WASHINGTON D.C. (/) 516 (/) 9TH ST. (/) BRANCH (/) 1722 (/) PA. AVE. (/) TRADE MARK (beneath a drawing of intertwined dividers, right-angled ruler, and French curve). The inside of the lid is also stamped: MADE IN GREAT BRITAIN. A yellow rectangular label is printed: To H.M. Government Science & Art Depnt. Council of India, Admiralty, &c. (/) MADE BY (/) W. F. STANLEY, (/) Optical, Philosophical & Mathematical (/) INSTRUMENT MANUFACTURER, (/) ENGINE DIVIDER, &c. (/) MATHEMATICAL DEPARTMENT, GREAT TURNSTILE, HOLBORN, W.C.
- 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. According to Boyd's Directory of the District of Columbia, Fred A. Schmidt, vendor of draftsmen's supplies, moved from 504 9th Street N.W. to 516 9th Street, with a branch at 1722 Pennsylvania Avenue, between 1895 and 1900.
- According to the donor, this example came from the family of her first husband, Fred Robert Troll (1920–1971), a sanitary engineer who attended Columbia University. The original purchaser may have been his father, Frank Troll, or his uncle, who was an artist who traveled frequently.
- See also MA*311958, MA*316575, and MA*313751.
- References: William Ford Stanley, Mathematical Drawing and Measuring Instruments, 6th ed. (London: E. & F. N. Spon, 1888), 248–249; W. F. 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.
- Currently not on view
- date made
- Stanley, William Ford
- ID Number
- catalog number
- maker number
- accession number
- Data Source
- National Museum of American History, Kenneth E. Behring Center