Index by Purpose

While many slide rules were made as general calculating instruments, for multiplying numbers and solving equations with squares, cubes, trigonometric functions, and logarithms, many others were made to ease the calculations associated with a specific task. Click on items in the list below to see rules in the collection with an identifiable specialized purpose. For comparison, a few illustrative examples of all-purpose slide rules are shown under the link to General Calculation.

AccessibilityEngineering, ElectricalNavigation
AgricultureEngineering, GeneralNovelty Forms
AstronomyFirefightingPromotion & Sales
Business & Office WorkGaugingShipping
CarpentryGeneral CalculationStatistics
ComputingGovernmentSurveying
ConstructionManufacturingTelevision
Conversion ChartsMetalworkingTransportation
EducationMeteorologyWagering
Engineering, AeronauticalMilitary Applications 
This is a twelve-inch, four-sided boxwood slide rule used in England for measuring and taxing barrels of liquid. Each of the four slides has a brass guide at one end, and the various special points on the rules are marked with inset brass pegs.
Description
This is a twelve-inch, four-sided boxwood slide rule used in England for measuring and taxing barrels of liquid. Each of the four slides has a brass guide at one end, and the various special points on the rules are marked with inset brass pegs. On one side, the base has a D scale, logarithmically divided from 1 to 3.2 and from 3.2 to 10. Point 18.789 is marked G, the circular gauge point, for determining the mean diameter of a barrel. Point 46.3 is marked MS, for the side of a square vessel that contains a solid bushel per inch of depth, and point 52.32 is marked MR, for the side of a square vessel that contains a malt bushel per inch of depth. The slide has two identical B scales, logarithmically divided from 1 to 10. Point 277.42 is marked G for the imperial gallon.
On the second side, the base has logarithmic scales that run from 1 to 8 and from 8 to 100. It is labeled SEGT ST (Segments Standing) at the top left and SS at the bottom right. The slide has two identical C scales, logarithmically divided from 1 to 9. This side was used to estimate the volume of a barrel that was standing vertically and partially filled. The back of the slide lists gauge points, divisors, and factors for circles for malt and for gall (another substance used in making alcoholic beverages) in circular and square containers.
On the third side, the base has an A scale, logarithmically divided from 1 to 10, and an MD (Malt Depth) scale that runs logarithmically in the opposite direction from somewhat less than 3 to 20. Point 2219 is marked B, for the number of cubic inches in a bushel under the imperial system of measurement, and point 277.42 is marked G, for the imperial gallon. The slide has two identical C scales, logarithmically divided from 1 to 9. The back of the slide has a scale of inches, a scale labeled SPH[EROI]D, and a scale labeled 2D VAR[IETY]. These scales are for determining the diameters of two different shapes of barrels. Underneath the slide is marked: COOK. MAKER TO THE HONBLE BOARD OF EXCISE. LATE WELLINGTON CROWN COURT SOHO LONDON NO 2950.
On the fourth side, the base has logarithmic scales that run from 0 to 4 and from 4 to 100. It is labeled SEGT LY (Segments Lying) at the top left and SL at the bottom right. The slide has two identical B scales, logarithmically divided from 1 to 9. Underneath the slide, points 3.9 and 99 are connected by a line marked with H.
The use of the Imperial system of units dates this slide rule to after 1824. It is of the style developed by Thomas Everard in 1683 and, at 12 inches, represents one of the two standard "pocket" sizes (the other was 9"). Laban Cook(e) succeeded Alexander Wellington (d. 1825) as a Maker to the English Board of Excise and remained in business until 1834. Compare to the older rule for gauging and ullage (the amount a container is lacking to be full), 319510.
References: D. Baxandall, Catalogue of the Collections in the Science Museum: Mathematics I. Calculating Machines and Instruments (London, 1926), 42; Colin Barnes, "The Customs and Excise Gauging Slide Rule," Journal of the Oughtred Society 4, no. 2 (1995): 53–57; Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 72, 245; Gloria Clifton, Dictionary of British Scientific Instrument Makers (London: National Maritime Museum, 1995), 64.
Location
Currently not on view
date made
1825-1834
maker
Cook, Laban
ID Number
1980.0588.04
catalog number
1980.0588.04
accession number
1980.0588
This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder.
Description
This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder. The telescoping rule is ten inches long when extended and equivalent to a rectangular slide rule 66 feet in length. Two short white lines on the tube and a black mark on the chrome cap at the end of the cylinder serve as the indicator. A paper spiral logarithmic scale is attached to the top half of the holder. A second, linear and logarithmic, paper scale is attached to the cylinder. The logarithmic scales are used to multiply and divide, and the linear scale is used to find logarithms.
At the top of the cylinder is printed: PATENT No 183723. At the bottom of the cylinder is printed: OTIS KING'S POCKET CALCULATOR; SCALE No 430. The top of the scale on the holder is printed: SCALE No 429; COPYRIGHT. The bottom is printed: OTIS KING'S PATENT No 183723. The end of the holder is engraved: MADE IN (/) Y9481 (/) ENGLAND.
Otis Carter Formby King invented this form of slide rule in 1921, and Carbic Limited of London, England, manufactured it until 1972. The serial number, Y9481, suggests a date about 1965–1969 for this example. A collector of computing devices donated it to the Smithsonian.
See also 1987.0788.01 and 1989.3049.02. For documentation, see 1981.0922.10 and 1981.0922.11.
References: Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 274, 281; Otis Carter Formby King, "Calculating Apparatus," (U.S. Patent 1,645,009 issued October 11, 1927); Richard F. Lyon, "Dating of the Otis King: An Alternative Theory Developed Through Use of the Internet," Journal of the Oughtred Society 7, no. 1 (1998): 33–38; Dick Lyon, "Otis King's Patent Calculator," http://www.svpal.org/~dickel/OK/OtisKing.html.
Location
Currently not on view
date made
ca 1965-1968
maker
Carbic Limited
ID Number
1981.0922.09
catalog number
1981.0922.09
accession number
1981.0922
The cover of this eight-page pamphlet is blue and black. It reads: HOW THE (/) OTIS KING (/) SPIRAL (/) SLIDE RULE (/) SAVES TIME (/) AND MISTAKES (/) IN ALL (/) CALCULATIONS (/) SIMPLE (/) QUICK (/) ACCURATE.
Description
The cover of this eight-page pamphlet is blue and black. It reads: HOW THE (/) OTIS KING (/) SPIRAL (/) SLIDE RULE (/) SAVES TIME (/) AND MISTAKES (/) IN ALL (/) CALCULATIONS (/) SIMPLE (/) QUICK (/) ACCURATE. The text describes the features and advantages of the Otis King cylindrical slide rule. Drawings demonstrate the three steps required to make calculations with the instrument. The pamphlet also lists 13 sample problems the Otis King Pocket Calculator could solve, 37 companies that were major customers of the rule, and 50 professions that usefully employed the rule. The back page carries five anonymous testimonials.
This pamphlet arrived with 1981.0922.09 and 1981.0922.11. It is exactly the same as 1989.3049.04, except that it is not stamped with information about where the rule was purchased.
Location
Currently not on view
date made
1965-1970
maker
Carbic Limited
ID Number
1981.0922.10
accession number
1981.0922
catalog number
1981.0922.10
This 16-page pamphlet was printed on light green paper by Carbic Limited, the London manufacturer of the cylindrical slide rule invented by Otis King. It is titled: The Otis King Calculator: Instructions for Use.
Description
This 16-page pamphlet was printed on light green paper by Carbic Limited, the London manufacturer of the cylindrical slide rule invented by Otis King. It is titled: The Otis King Calculator: Instructions for Use. This form of pamphlet is typically found with King Calculators manufactured later than those that sold with Carbic's eight-page pamphlet. (See 1987.0788.06.) Thus, it was printed no earlier than the late 1960s. This pamphlet did, though, appear before the pound sterling was decimalized in 1971.
An introduction to the instrument has been added, and explanations have been expanded for multiplication and division, logarithms, and understanding the scales. The further examples are nearly identical to those in the earlier form of instructions. The explanations of how to use the logarithmic capabilities of Model L are the same except that the word "unity" has been replaced by the number 1. Discussions of compound roots and approximation have been added, and the explanation of finding the decimal point is expanded.
Reference: Dick Lyon, "Otis King's Patent Calculator," http://www.svpal.org/~dickel/OK/OtisKing.html.
Location
Currently not on view
date made
ca 1965-1970
maker
Carbic Limited
ID Number
1981.0922.11
accession number
1981.0922
catalog number
1981.0922.11
This is a two-foot, two-fold boxwood rule with a brass hinge and endpieces. Half of one side is a slide rule with A and D scales on the base and B and C scales on the slide.
Description
This is a two-foot, two-fold boxwood rule with a brass hinge and endpieces. Half of one side is a slide rule with A and D scales on the base and B and C scales on the slide. As with MA.306697.01, the C scale is the same as the A and B scales (the square of the D scale), instead of the same as the D scale, as on modern Mannheim slide rules. Below the D scale is marked: SQUARE CYLINDER GLOBE (3 times) ROUTLEDGE'S ENGINEER.
The first three marks form headings for the tables on the other half of this side when the instrument is folded. The tables give conversion factors from the volumes of geometric solids to units of volume, in both the "old" and imperial systems; conversion factors from the volumes of geometric solids to the weights in pounds of various substances; the areas of polygons from 5 to 12 sides; the gauge points of a circle; and gauge points for pumping engines, to find the diameters of steam cylinders that will work pumps of specified diameter at 7 pounds per square inch.
The other side has a scale of 24 inches along one edge, divided to sixteenths of an inch for 9 inches and to eighths of an inch for the rest of the scale. There are also scales for making scale drawings that are 1, 3/4, 1/2, and 1/4 inches to the foot. This side is marked: T. ASTON THE ORIGINAL MAKER WARRANTED. One outside edge has scales for 10 and 12 parts to the inch; the other outside edge divides one foot into 100 parts.
This form of slide rule was invented by Joshua Routledge, a seller of iron goods, in 1808 or 1809. He discussed it in the 1813 (4th) edition of Instructions for the Engineer's Improved Sliding Rule. According to Gloria Clifton, there were two rule makers named Thomas Aston, presumably a father and son, who were in business at various addresses in Birmingham, England, from 1818 to 1862. The references to pre-imperial system units of measure suggest the rule might have been made shortly after the imperial system was adopted in 1824. This instrument was found in the home of Grace Speer, granddaughter of Alfred Speer (1823–1910), an inventor and wine merchant in Passaic, N.J.
References: John V. Knott, "Joshua Routledge 177[3]–1829," Journal of the Oughtred Society 4, no. 2 (1995): 25; Philip E. Stanley, "Carpenters' and Engineers' Slide Rules: Routledges' Rule," Chronicle of the Early American Industries Association 37, no. 2 (1984): 25–27; Gloria Clifton, Directory of British Scientific Instrument Makers (London: National Maritime Museum, 1995), 11–12; accession file.
Location
Currently not on view
date made
1824-1862
maker
Aston, T.
ID Number
1981.0934.01
catalog number
1981.0934.01
accession number
1981.0934
This square yellow cardboard instrument has circular discs that rotate about a metal pin. The edges of the instrument are bound in red morocco leather. The disc on one side, Fuller's Time Telegraph, is designed to rapidly compute intervals between dates on the calendar.
Description
This square yellow cardboard instrument has circular discs that rotate about a metal pin. The edges of the instrument are bound in red morocco leather. The disc on one side, Fuller's Time Telegraph, is designed to rapidly compute intervals between dates on the calendar. It has linear scales for the 365 days of the year around the edge of the disc and on the surrounding circle on the frame. In addition to the name of the instrument and directions for finding the number of days and weeks between two dates, there is a copyright mark: Entered according to Act of Congress in the year 1845 by John E. Fuller in the Clerk's Office of the District Court of the State of Massachusetts (/) Eng[rave]d by G. G. Smith, Boston.
The disc on the other side, Palmer's Computing Scale, has logarithmic scales for area, distance, weight, and volume. The scales are marked with various equivalents, such as 5,280 feet to one mile. The surrounding circle on the frame has logarithmic scales for days, months, and costs per hundredweight. The center of the disc is marked: IMPROVED BY (/) FULLER. Near the top of the disc is marked: Use the inner circle for Dollars, Cents & Mills, (/) or Pounds, Shillings & Pence. Below the name of the instrument is a copyright mark: Entered according to Act of Congress, in the year 1843, by Aaron Palmer in the Clerks [sic]Office of the District Court of the State of Massachusetts (/) and by J. E. Fuller 1847. (/) Engraved by George G. Smith 186 Washington St. Boston. Above the name of the instrument is a second copyright mark: Entered according to Act of Congress, in the year 1847, by J. E. Fuller, In the Clerks [sic] office of the District Court of the United States, for the Southern District of New York.
The instrument fits in a folder with a dark green cover marked: FULLER'S (/) COMPUTING (/) TELEGRAPH. Inside the front cover is a 21-page booklet. The booklet, published in London, is titled: Fuller's Computing Telegraph: Multiplication and Division by one Single Process . . . To Which is Added Fuller's Complete and Perpetual Calendar. The booklet advertises the instrument's capabilities, explains how to solve various problems, and provides more detailed instructions. There are various tables for mechanics and engineers, including squares and cubes and the pressure of steam engines, and rules for solving problems of machines and of geometry. A circular statistical chart for the 35 states of the United States, separated into free and slave states, is also provided. Inside the back cover is a pictorial chart of 178 "mechanical movements," depicting gears and other machines carrying out rectilinear and circular motions. W. Nicholson prepared the chart, O. Pelton engraved it, and John E. Fuller published it.
This instrument was one of the first circular slide rules sold in the United States. It was introduced by Aaron Palmer of Boston, who made a prototype in 1841, took out a copyright for a computing scale in 1843, and published an account of it in 1844. He exhibited both the original and a smaller version at the 18th American Institute Fair, held in New York, N.Y., in 1845. There it may have attracted the attention of John Emery Fuller (1799–1878). By 1846, Fuller had acquired rights to Palmer's instrument and published an account of his improvements. He also added the time telegraph, which he had copyrighted in 1845. Fuller copyrighted the revised form of Palmer's scale in 1847. He exhibited the slide rule at the Crystal Palace exhibition in London in 1851 and prepared an English version of the instrument.
Bobby Feazel counted seven separate issues of the instrument, the four by Palmer listed above and three by Fuller (1847, 1848, 1871). The marks on this example correspond to the sixth issue, which was the English version and was manufactured between 1848 and 1871. The references in the instruction booklet to slave states and data from the 1860 Census suggest a date between 1861 and 1865.
References: Aaron Palmer, A Key to the Endless, Self-computing Scale, Showing Its Application to the Different Rules of Arithmetic, &c. (Boston: Smith & Palmer, 1844); Scientific American 1, no. 8 (October 16, 1845): 3; "The Eighteenth Annual Fair of the American Institute," American Whig Review 2, no. 5 (November 1845): 538–542, on 541; John E. Fuller, Improvement to Palmer's Endless Self-computing Scale and Key: Adapting It to the Different Professions . . . and Also to Colleges, Academies and Schools, With a Time Telegraph, Making, by Uniting the Two, a Computing Telegraph (New York, 1846; new ed., New York, 1851); "Fuller's Computing Telegraph," The Public Ledger, St. John's, Newfoundland, August 11, 1857, 2; Florian Cajori, "Aaron Palmer's Computing Scale" and "John E. Fuller's Circular Slide Rules," Colorado College Publication: Engineering Series 1 (1909): 111–122; Bobby Feazel, "Palmer's Computing Scale," Journal of the Oughtred Society 3, no. 1 (1994): 9–17; 4, no. 1 (1995): 5–8.
Location
Currently not on view
date made
1861-1865
maker
George Philip and Son
ID Number
1987.0284.01
catalog number
1987.0284.01
accession number
1987.0284
This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder.
Description
This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder. The rule is ten inches long when extended and equivalent to a linear slide rule 66 feet in length. Two short white lines on the tube and a black mark on the chrome cap at the end of the cylinder serve as the indicator. A paper spiral logarithmic scale is attached to the top half of the holder. A second, linear and logarithmic, paper scale is attached to the cylinder. The logarithmic scales are used to multiply and divide, and the linear scale is used to find logarithms.
The end of the cylinder is engraved: MADE IN (/) ENGLAND. At the top of the cylinder is printed: PATENT No 183723. At the bottom of the cylinder is printed: OTIS KING'S POCKET CALCULATOR; SCALE No 430. The top of the scale on the holder is printed: SCALE No 429; COPYRIGHT. The bottom is printed: OTIS KING'S PATENT No 183723. The end of the holder is machine engraved: T/0503. Engraved by hand (and upside-down to the serial number) is: C73.
The instrument is stored in a rectangular black cardboard box. A label on one end reads: Otis King's (/) Calculator (/) Model "L" (/) No. T0503. The slide rule arrived with instructions, 1987.0788.06, and an advertising flyer, 1987.0788.07. See also 1989.3049.02 and 1981.0922.09.
Otis Carter Formby King (b. 1876) of Coventry, England, received a British patent (183,723) for this instrument on August 31, 1922, and in 1923 he received patents 207,762 and 207,856 for improvements to the slide rule. From London, King filed a U.S. patent application, which he assigned to Carbic Limited, the London manufacturer of the slide rule, when that patent was granted in 1927. With co-inventor Bruce Hamer Leeson, King received U.S. Patent 1,820,354 for an "electrical remote control system" on August 25, 1931.
The serial number indicates that this example of Otis King's calculator was manufactured around 1960 to 1962. Howard Irving Chapelle (1901–1975), a naval architect, maritime historian, and curator of what was then the National Museum of History and Technology, donated it to the Smithsonian around 1969 to 1970.
References: Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 274, 281; Otis Carter Formby King, "Calculating Apparatus," (U.S. Patent 1,645,009 issued October 11, 1927); Richard F. Lyon, "Dating of the Otis King: An Alternative Theory Developed Through Use of the Internet," Journal of the Oughtred Society 7, no. 1 (1998): 33–38; Dick Lyon, "Otis King's Patent Calculator," http://www.svpal.org/~dickel/OK/OtisKing.html.
Location
Currently not on view
date made
1960-1962
maker
Carbic Limited
ID Number
1987.0788.01
catalog number
1987.0788.01
accession number
1987.0788
This pamphlet folds out to eight pages and was printed on light green paper by Carbic Limited, the British manufacturer of Otis King's Pocket Calculator, a cylindrical slide rule.
Description
This pamphlet folds out to eight pages and was printed on light green paper by Carbic Limited, the British manufacturer of Otis King's Pocket Calculator, a cylindrical slide rule. Carbic's address on the pamphlet—171, Seymour Place, London, W.I.—is scratched out and reprinted as 54, Dundonald Road, London, S.W.19. Dundonald Road was the last known location for Carbic, and the company was there by 1959. The calculator was available by mail order in 1960 for 62s. 6d. (roughly $175.00).
The pamphlet provides details of the scales on the Model K (which performed multiplication and division) and the Model L (which also provided readings of logarithms for determining roots and powers). The examples also include problems of proportion, percentages, constant factors, and calculations in pounds sterling (before decimalization of British currency). The last three pages provide instructions for operating the instrument.
See also 1987.0788.01 and 1987.0788.07.
Reference: "Finding the Answer is Simplicity Itself," advertisement for the Otis King Pocket Calculator, The New Scientist 5, no. 121 (March 12, 1959): 548 and 8, no. 213 (December 15, 1960): 1568.
Location
Currently not on view
date made
ca 1960-1962
maker
Carbic Limited
ID Number
1987.0788.06
accession number
1987.0788
catalog number
1987.0788.06
This flyer, printed in blue ink on white paper, is titled: Simplify any Calculation with an Otis King. The text identifies potential users and describes the functions of this cylindrical slide rule.
Description
This flyer, printed in blue ink on white paper, is titled: Simplify any Calculation with an Otis King. The text identifies potential users and describes the functions of this cylindrical slide rule. The back of the flyer lists six sample problems the Otis King Pocket Calculator could solve. It is stamped with the address of an English dealer of scientific instruments: H. T. POCKETT. (/) 25. NELSON ROAD. (/) GREENWICH. S.E.10. The price is listed as 47s. 6d. postpaid.
The flyer arrived with 1987.0788.01 and probably dates to the same period, from about 1960 to 1962. See also 1987.0788.06.
Location
Currently not on view
date made
ca 1960-1962
maker
Carbic Limited
ID Number
1987.0788.07
accession number
1987.0788
catalog number
1987.0788.07
This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder. The rule is ten inches long when extended.
Description
This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder. The rule is ten inches long when extended. Two short white lines on the tube and a black mark on the chrome cap at the end of the cylinder serve as the indicator. A paper spiral logarithmic scale is attached to the top half of the holder. A second, linear and logarithmic, paper scale is attached to the cylinder. The logarithmic scales are used to multiply and divide, and the linear scale is used to find logarithms.
At the top of the cylinder is printed: PATENT No 183723. At the bottom of the cylinder is printed: OTIS KING'S POCKET CALCULATOR; SCALE No 430. The top of the scale on the holder is printed: SCALE No 429; COPYRIGHT. The bottom is printed: OTIS KING'S PATENT No 183723. The end of the holder is machine engraved: MADE IN (/) Y5466 (/) ENGLAND.
The instrument arrived in a mailing tube with return address: CALCULATOR COMPANY (/) POST OFFICE BOX 593 (/) LAKEWOOD, CALIFORNIA 90714.
Otis Carter Formby King invented this form of slide rule in 1921, and Carbic Limited of London, England, manufactured it until 1972. The Calculator Company served as Carbic's distributor in the United States. The 5-digit ZIP code on the mailing tube indicates this example was made after 1963. The serial number, Y5466, suggests a date around 1965–1969.
See also 1987.0788.01 and 1981.0922.09. The slide rule was received with a trifold instruction sheet, 1989.3049.03, and an advertising pamphlet, 1989.3049.04.
References: Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 44; Richard F. Lyon, "Dating of the Otis King: An Alternative Theory Developed Through Use of the Internet," Journal of the Oughtred Society 7, no. 1 (1998): 33–38; Dick Lyon, "Otis King's Patent Calculator," http://www.svpal.org/~dickel/OK/OtisKing.html.
Location
Currently not on view
date made
1965-1968
maker
Carbic Limited
ID Number
1989.3049.02
nonaccession number
1989.3049
catalog number
1989.3049.02
This trifold pamphlet reprints the text found in 1987.0788.06, except for the section on [Pounds] Sterling Calculations, which is omitted. The columns of text are also laid out slightly differently, so that the page length is shortened from eight pages to six.
Description
This trifold pamphlet reprints the text found in 1987.0788.06, except for the section on [Pounds] Sterling Calculations, which is omitted. The columns of text are also laid out slightly differently, so that the page length is shortened from eight pages to six. These instructions accompanied 1989.3049.02. See also 1989.3049.04.
Location
Currently not on view
date made
ca 1965-1968
maker
Carbic Limited
ID Number
1989.3049.03
nonaccession number
1989.3054
catalog number
1989.3054.01
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.
Description
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.
Location
Currently not on view
date made
1898
maker
Stanley, William Ford
ID Number
1998.0046.01
catalog number
1998.0046.01
maker number
1008/98
accession number
1998.0046
From the late 18th to the mid-19th centuries, British engineers began to use slide rules. This ivory and silver instrument is a four-fold engineer's rule that unfolds to a length of 24 inches.
Description
From the late 18th to the mid-19th centuries, British engineers began to use slide rules. This ivory and silver instrument is a four-fold engineer's rule that unfolds to a length of 24 inches. On half of one side is a slide rule with A and D scales on the base and B and C scales on the slide. The A and D scales seem to run continuously, although the slide only moves on the second six inches of the rule.
The words IRON and ROPE appear several times along the edge of the A scale. Along the edge of the D scale is marked: DESCRIPTION SQUARE CYL[I]ND[ER] GLOBE SQUARE CYL[I]ND[ER] WEIGHT STRAIN WORK INCLIN[E] POLYGON SIDE GOVERNORS H[ORSE]P[OWER] ENGIN[E]S STE[A]M TEM[PERATURE]. When the rule is folded, these markings correspond to the tables on the other half of the instrument.
The other half of this side has a table of gauge points for the A scale. Instructions printed on the rule suggest that calculations on the slide rule were intended to be made with calipers. Additional tables and instructions for working with ropes and chains are on this half, which is marked: IMPROVED & ARRANG[E]D (/) BY RT HAWTHORN (/) CIVIL ENGINEER (/) NEWCASTLE TYNE.
The other side has a scale of 24 inches divided to eighths of an inch along the edge. The metal joint has a protractor divided in increments of 5 degrees and marked by tens from 0 to 180. When the instrument is folded around the joint, there are tables for the extreme strain possible in bars and beams of various substances and for equivalent measures. The joint is marked: G. R. STEPHENSON (/) ENGINEER (/) Adam Pensom.
In 1832 civil engineer Robert Hawthorn (1796–1867) designed a new form of slide rule for manufacturing locomotives and other engines. In 1859 dealers sold the rule for 5 shillings and 6 pence. The names on the joint may refer to the British civil engineer George Robert Stephenson (1819–1905), nephew to the engineer George Stephenson (1781–1848), who sought mechanical advice from Hawthorn's father, and to Adam Pensom (b. 1824), who was a retired gas engineer living in London, according to the 1881 British census. The Smithsonian acquired this object in 1973.
References: Robert Hawthorn, Instructions for the Use of the Mechanics' Sliding Rule (Newcastle-upon-Tyne, 1841), available online at http://www.physics.uq.edu.au/physics_museum/hawthorne/; "Mr. Robert Hawthorn," Minutes of the Proceedings of the Institution of Civil Engineers 27 (1867–1868): 590–592; advertisement by John Archbutt, The Mechanics' Magazine, n.s., 1, no. 10 (March 4, 1859): 486; Peter M. Hopp, Joint Slide Rules (Jeremy Mills Publishing: Lindley, Huddersfield, West Yorkshire, 2009).
Location
Currently not on view
date made
after 1832
maker
Hawthorn, Robert
ID Number
MA.306697.01
accession number
306697
catalog number
306697.01
This is the U.S. patent model for a cylindrical slide rule invented by George Fuller (1829–1907), a British civil engineer and professor of engineering at Queen's College, Belfast. Fuller received patents in Great Britain (no. 1044) in 1878 and in the United States in 1879. W.
Description
This is the U.S. patent model for a cylindrical slide rule invented by George Fuller (1829–1907), a British civil engineer and professor of engineering at Queen's College, Belfast. Fuller received patents in Great Britain (no. 1044) in 1878 and in the United States in 1879. W. F. Stanley of London manufactured the rule from 1879 until 1975, and it was marketed in the United States by Keuffel & Esser, Dietzgen, and other dealers.
The model has a wooden handle and shaft, with a wooden cylinder that slides up and down the shaft. A paper covered with scales fits around the cylinder. The lower edge of the cylinder has a scale of equal parts. The remainder bears a spiral scale divided logarithmically. A rectangular clear plastic pointer has broken from its attachment on the handle and is tucked into a red ribbon tied around the cylinder. A paper patent tag is marked: No. 291.246; 1879 (/) G. Fuller. (/) Calculators. (/) Patented Sept 2. (/) 1879. A printed description from the patent application of April 16, 1878, is glued to the back of the tag. The tag is attached to the handle with a red ribbon.
L. Leland Locke, a New York mathematics teacher and historian of mathematics, collected this patent model and intended it for the Museums of the Peaceful Arts in New York City. When that institution encountered financial difficulties in 1940, Locke gave a collection of objects, including this model, to the Smithsonian Institution.
For production models of this instrument, see 313751, 316575, and 1998.0046.01.
References: George Fuller, "Improvement in Calculators" (U.S. Patent 219,246 issued September 2, 1879); The Report of the President of Queen's College, Belfast, for the Year Ending October, 1876 (Dublin, 1877), 9, 29–30, 107–110; James J. Fenton, "Fuller's Calculating Slide-Rule," Transactions and Proceedings of the Royal Society of Victoria 22 (1886): 57–61; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 42–43.
Location
Currently not on view
date made
1878
patentee
Fuller, George
maker
Fuller, George
ID Number
MA.311958
accession number
155183
catalog number
311958
In 1881, Edwin Thacher, a "computing engineer" for the Keystone Bridge Company in Pittsburgh, Pennsylvania, received a patent for an improvement in slide rules. Thacher was a graduate of Rennselaer Polytechnic Institute who spent much of his career designing railway bridges.
Description
In 1881, Edwin Thacher, a "computing engineer" for the Keystone Bridge Company in Pittsburgh, Pennsylvania, received a patent for an improvement in slide rules. Thacher was a graduate of Rennselaer Polytechnic Institute who spent much of his career designing railway bridges. To assist in his calculations, he designed a cylindrical slide rule. Thacher's rule, though it fit on a desk, was equivalent to a conventional slide rule over 59 feet long. It had scales for multiplication and division and another scale, with divisions twice as large, for use in finding squares and square roots. But it had no trigonometric scales.
To produce his "calculating instrument," Thacher turned to the London firm of W. F. Stanley. The company even designed a special dividing engine for preparing the scales for the instrument. These were printed on paper sheets, which were pasted to the drum and the slats. In this example, the paper is also printed in italics on the right side: Patented by Edwin Thatcher [sic], C.E. Nov. 1st 1881. Divided by W. F. Stanley, London, 1882.
The drum is rotated with wooden handles. The cylinder of slats is held in place with a brass frame, which is affixed to a wooden base. A paper of DIRECTIONS AND RULES FOR OPERATING is lacquered to the front of the base. The rear of the base bears a small silver metal label engraved: Keuffel & Esser (/) New York. F. F. NICKEL is painted underneath the base.
Keuffel & Esser Company of New York sold versions of the Thacher cylindrical slide rule from at least 1883 until about 1950. There were two models, one with a magnifying glass (K&E model 1741, later K&E model 4013), and one without (K&E model 1740, later K&E 4012). This is a model 1740. The front right corner of the instrument's metal frame is engraved with the number 107. A paper K&E label on the inside lid of the instrument's mahogany case is marked in ink: 1740/661 (/) Thachers (/) Calculating (/)Instr. The top front of the bottom of the case is also carved with 661. In 1887, the model 1740 sold for $30.00.
Frank Ferdinand Nickel purchased this example around 1883 and donated it to the Smithsonian in 1945, through his son, Henry W. Nickel. The elder Nickel was born in Hanau, Germany, in 1857. He came to the United States around 1883 and worked as a mechanical engineer in New York, Ohio, Pennsylvania, and New Jersey. He also taught at Columbia University in the 1910s. He wrote Direct-Acting Steam Pumps (New York: McGraw-Hill, 1915).
See also 1987.0107.08 and 1987.0808.01.
References: Edwin Thacher, "Slide-Rule" (U.S. Patent 249,117 issued November 1, 1881); "Thacher's Calculating Instrument or Cylindrical Slide Rule," Engineering News 16 (18 December 1886): 410; Wayne E. Feely, "Thacher Cylindrical Slide Rules," The Chronicle of the Early American Industries Association 50 (1997): 125–127; Wilfred Scott Downs, ed., "Nickel, Frank F.," Who's Who in Engineering, vol. 3 (New York, 1931), 957; Catalogue of Keuffel & Esser (New York, 1887), 128. This was the first K&E catalog to list the model 1740.
Location
Currently not on view
date made
ca 1883
maker
Stanley, William Ford
Keuffel & Esser Co.
ID Number
MA.312866
accession number
169701
catalog number
312866
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.
Description
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). This length permitted computations up to four or five significant digits.
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 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, removable, nickel-plated brass cylinder is inside the instrument and attached to the base. There is no case.
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: 1389. The top of the long brass index is engraved: 1389 (/) 1901. According to Wayne Feely, these numbers indicate the instrument has serial number 1389 and was made by Stanley in 1901. A white celluloid tag affixed to the handle reads: KEUFFEL & ESSER CO. (/) ST. LOUIS. CHICAGO. (/) NEW YORK. (/) U.S.A. In the 1901 Keuffel & Esser catalog, Fuller's Spiral Slide Rule is listed as Model 4015 and priced at $30.00.
See also 311958, 1998.0046.01, and 316575.
References: 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, 1901), 290; James J. Fenton, "Fuller's Calculating Slide-Rule," Transactions and Proceedings of the Royal Society of Victoria 22 (1886): 57–61; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 42–43; George Fuller, Instructions for the Use of the Fuller Calculator (London: W. F. Stanley & Co., Ltd., [about 1950]), http://www.mccoys-kecatalogs.com/KEManuals/4015/4015.htm. An 1879 first edition of the instructions manual was received with the instrument and is stored in the accession file.
Location
Currently not on view
date made
1901
inventor
Fuller, George
retailer
Keuffel & Esser Co.
maker
Stanley, William Ford
ID Number
MA.313751
catalog number
313751
maker number
1380/1901
accession number
179682
This wooden instrument is faced on both sides with white celluloid that is attached with brass screws instead of glue.
Description
This wooden instrument is faced on both sides with white celluloid that is attached with brass screws instead of glue. On one side are 20-inch scales: cosine and sine scales on the upper part of the base, two identical logarithmic scales (in three cycles) labeled TIME SCALE on the slide, and a tangent scale on the lower part of the base. The slide is in two pieces, so the second Time Scale may be removed and adjusted relative to the first Time Scale with the aid of a brass thumbscrew.
Three glass indicators are in three-sided brass frames, two on the upper part of the base and one on the lower part of the base. The top of the base is marked: J. HICKS (/) LONDON. It is also marked: PILOT BALLOON SLIDE RULE MO (O is superimposed on M) 505. MO is an abbreviation for Meteorological Office, and 505 may be a serial number. An inventory sticker on the back reads: DEPARTMENT OF AGRICULTURE (/) US. The inventory number has been cut away. The instrument fits in a wooden case covered with black leather and lined on one side with purple satin.
In the 20th century, the Meteorological Office of Great Britain used pilot balloon slide rules to convert azimuth and elevation readings (taken with theodolites during the ascent of a pilot balloon) into data on wind velocity and direction. James Joseph Hicks (1825–1916), who began supplying instruments to the Office in 1869, made the first pilot balloon slide rule in 1915 from a design by Francis John Welsh Whipple, the Superintendent of Instruments.
After Hicks died, W. F. Stanley & Co. took over manufacture of this rule, called the Mark I, but retained the Hicks name. Additional labels were placed on the scales, such as "Azimuth." By 1927, A. G. Thornton Ltd. and other firms were making the Mark II, which had one slide and four indicators. Production of the Mark I may have continued until 1938.
The U.S. Weather Bureau was a part of the U.S. Department of Agriculture until 1940, when it was transferred to the U.S. Department of Commerce. This instrument apparently was not adopted by American meteorologists, since the Bureau used the Keuffel & Esser polyphase duplex slide rule to convert observations. For examples of that type of slide rule, see MA.318476, MA.321778, and 1981.0933.03. For an American theodolite used to observe pilot balloons, see PH.308184.
References: Martin Brenner, "Pilot Balloon Slide Rules," http://www.csulb.edu/~mbrenner/slide.htm; Malcolm Walker, History of the Meteorological Office (Cambridge: Cambridge University Press, 2012), 220; W. R. Gregg et al., Instructions for Aerological Observers, U.S. Department of Agriculture, Weather Bureau (Washington, D.C.: Government Printing Office, 1921), 78; Deborah J. Warner, "Altitude and Azimuth Instrument," National Museum of American History Physical Sciences Collection: Surveying and Geodesy , http://americanhistory.si.edu/collections/surveying/object.cfm?recordnumber=747475.
Location
Currently not on view
date made
1915-1927
inventor
Hicks, J. J.
maker
Stanley, William Ford
ID Number
MA.315905
catalog number
315905
accession number
222974
This is an eight-inch, four-sided boxwood slide rule used for measuring and taxing barrels of liquid. On one end of the rule, the slides on each side have been labeled with the four Roman numerals, I, II, III, and IV.
Description
This is an eight-inch, four-sided boxwood slide rule used for measuring and taxing barrels of liquid. On one end of the rule, the slides on each side have been labeled with the four Roman numerals, I, II, III, and IV. On side I, the base has logarithmic scales that run from 1 to 8 and from 8 to 100. It is labeled Seg St (Segments Standing) at the top left and SS at the bottom right. The slide has two identical C scales, logarithmically divided from 1 to 9. This side was used to estimate the volume of a barrel that was standing vertically and partially filled. The back of the slide lists calculating factors used in computing taxes on various liquors. For instance, the duty on one barrel of vinegar was equivalent to the duty on 7.56 barrels of small beer.
On side II, the base has logarithmic scales that run from 0 to 4 and from 4 to 100. The bottom right corner is labeled SL (Segments Lying) for estimating the volume of a partially filled barrel lying on its side. The slide has two identical B scales, logarithmically divided from 1 to 10. The point 231 is marked W, showing the number of cubic inches in a wine gallon, and pi (314) is marked with a C. The back of the slide has a table of gauge points for converting between volumes in cubic inches and numbers of gallons for substances in square or circular containers.
On side III, the base has an A scale, logarithmically divided from 1 to 10, and an MD (Malt Depth) scale that runs logarithmically in the opposite direction from somewhat less than 3 to 20. Point 2150 on the A scale is marked MB, for the number of cubic inches in a malt bushel, and point 282 is marked A, for the number of cubic inches in an ale gallon. The slide has two identical B scales, logarithmically divided from 1 to 9. The back of the slide has a scale of inches, a scale labeled Spheroid, and a scale labeled 2d Variety. These scales are for determining the diameters of two different shapes of barrels. Underneath the slide is marked: LEWIS & BRIGGS : Makers. No. 52. BOW. LANE. Cheapside. LONDON.
On side IV, the base has a D scale, logarithmically divided from 1 to 3.2 and from 3.2 to 10. Point 17.15 is marked WG, for the diameter in inches of a cylinder that contains one gallon of wine when filled to a depth of one inch. Point 18.95 is marked AG for the diameter of a cylinder containing one gallon of ale. Point 46.3 is marked MS, for the side of a square vessel that contains a solid bushel per inch of depth, and point 52.32 is marked MR, for the side of a square vessel that contains a malt bushel per inch of depth.
The slide has two identical C scales, logarithmically divided from 1 to 10. The back of the slide has a table of divisors for converting between volumes in cubic inches and numbers of gallons for substances in square or circular containers. The numbers in this table are squares of the gauge points in the table on the back of the slide on side II. Underneath the slide is marked: Willm. Wright : April. 30. 1795.
According to Gloria Clifton, the firm of Lewis & Briggs operated in London from at least 1795 to 1799. The Smithsonian acquired this object in 1961.
References: Colin Barnes, "The Customs and Excise Gauging Slide Rule," Journal of the Oughtred Society 4, no. 2 (1995): 53–57; Ron Manley, "Gauging," http://www.sliderules.info/a-to-z/gauging.htm; Gloria Clifton, Directory of British Scientific Instrument Makers (London: National Maritime Museum, 1995), 167.
Location
Currently not on view
date made
1795
maker
Lewis & Briggs
ID Number
MA.319510
catalog number
319510
accession number
239015
This yew rule has straight brass ends and two slides, which fit between the three parts of the base.
Description
This yew rule has straight brass ends and two slides, which fit between the three parts of the base. On one side, the top scale on the base (labeled A), the two scales on the upper slide (labeled E), the first scale in the middle of the base (labeled D), and the two scales on the second scale (labeled B and C) are identical logarithmic scales that run from 1 to 10 twice in the length of the rule. The second scale in the middle runs from 1 to 100 and is labeled SEGT ST (segments standing). The lowest scale on the base is labeled SEGT LY (segments lying).
These scales are used with the slides to find the volume of the liquid in a cask that is not full, either when it is standing on its base or lying horizontally. The ImB and ImG points, for just over 2200 cubic inches in an imperial bushel and 277.42 cubic inches in an imperial gallon, are marked on the A scale. On the D scale, point 18.95 is marked IG for the diameter of a cylinder containing one imperial gallon; point 46.3 is marked MS, for the side of a square vessel that contains one solid bushel per inch of depth; and point 52.32 is marked MR, for the side of a square vessel that contains one malt bushel per inch of depth.
The reverse side of the rule has a scale on the base labeled A that runs logarithmically from 1 to 10. Both slides have identical scales (the one on the upper slide is labeled C) that run from over 80 (UNDER PROOF) down to 0 (PROOF) and then up to 70 (OVER PROOF). The middle of the base has a scale labeled B that runs logarithmically from 4 to 40 and a scale labeled C that runs logarithmically from 300 to 30. The bottom of the base has a scale, also labeled C, that runs logarithmically from 100 to 10. There is no indicator.
One edge of the instrument has a scale labeled SPHD and a scale labeled 2ND VARIETY. These scales are for determining the diameters of two different shapes of barrels. The other edge is marked: L. LUMLEY & CO LTD 1 AMERICA SQUARE LONDON. L. Lumley & Company, a distributor of packing cases and related materials for bottling, was in business in London from at least 1884 though 1929.
For slide rules with similar two-slide designs but different purposes, see MA.318478 and 1987.0693.01. For earlier gauger's rules, see MA.319510 and 1980.0588.04.
Reference: Ronald E. Manley, "Gauging," http://www.sliderules.info/a-to-z/gauging.htm.
Location
Currently not on view
date made
1884-1929
maker
L. Lumley & Company Limited
ID Number
MA.320637
catalog number
320637
accession number
242721
This instrument consists of a wooden base to which a flat rectangular scale printed on white celluloid is attached. The scale is divided logarithmically and arranged in 20 parallel lines. Each line is about five inches long.
Description
This instrument consists of a wooden base to which a flat rectangular scale printed on white celluloid is attached. The scale is divided logarithmically and arranged in 20 parallel lines. Each line is about five inches long. A wooden frame slides backward and forward over the base. Within this frame is a second frame, which has a clear celluloid window. Four index marks are drawn on the window. A loose metal wedge with a pin attached serves as a pointer, and it may be placed at any point on the window. The scales are marked: THE COOPER 100 INCH SLIDE RULE (/) PATENTED.
The feet of the base are lined with green felt. The instrument fits in a leather-covered cardboard box that is lined with white felt. A sticker inside the lid reads: WILLIAM DUBILIER (/) 72 Esplanade (/) NEW ROCHELLE, N. Y. There is also a note that reads: TELEPHONE, PARK 1081. (/) WIRELESS CALL, 5AU. (/) 94, ADDISON ROAD (/) KENSINGTON, W. 14. (/) 24/12/22 (/) To W. D. (/) With very best wishes for (/) Xmas and the New Year. (/) W.v.P.
William Dubilier (1888–1969), the donor of this instrument, was an American electrical engineer and inventor who received this instrument from a friend in Great Britain in 1922. By 1923, W. F. Stanley & Co. made this rule and stamped the outer frame with its mark. Although the rule worked well for multiplication and percentage problems, it was difficult to set the rule accurately for more complex calculations. At the relatively high price of £4, the instrument probably never sold widely. No patents for the device have been found. For the instruction manual, see MA.259739.01.
References: Werner H. Rudowski, "The Cooper 100-inch Slide Rule: An Update," Slide Rule Gazette 8 (Autumn 2007): 25–27; Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 116; "William Dubilier, Inventor, Is Dead," New York Times (July 27, 1969), 65; accession file.
Location
Currently not on view
date made
1922
maker
Stanley, William Ford
ID Number
MA.326237
catalog number
326237
accession number
259739
In the late 19th and early 20th centuries, several circular slide rules were made to resemble pocket watches. Fowler & Co., of Manchester, England, was a particularly notable manufacturer of this type of slide rule.
Description
In the late 19th and early 20th centuries, several circular slide rules were made to resemble pocket watches. Fowler & Co., of Manchester, England, was a particularly notable manufacturer of this type of slide rule. The company was in business from 1898 to 1988 and made a large variety of calculators, although the labor-intensive nature of its manufacturing process produced expensive instruments that never sold in large numbers.
This example is the "long scale" model, consisting of a metal case with a ring, two knobs, and two rotating paper discs covered with glass. The front has a short logarithmic scale and a long logarithmic scale, laid out in six concentric circles rather than in a spiral. These scales are rotated by the knob on the left. The glass is marked with two hairlines. The interior of the disc reads: FOWLER'S (/) LONG SCALE CALCULATOR (/) PATENT (/) FOWLER & Co MANCHESTER.
The other knob rotates the seven scales on the back of the instrument: multiplication and division, reciprocals, logarithms, square roots, logarithmic sines, logarithmic tangents, and a second scale for logarithmic sines. The interior is marked: FOWLER'S (/) CALCULATOR (/) PATENT (/) FOWLER & Co MANCHESTER. There is one hairline indicator on the glass. The slide rule is with a tarnished square metal case, lined with purple velvet. The outside of the case is engraved: Fowler's (/) CALCULATOR. The inside is stamped: Fowler & Co. (/) CALCULATOR (/) SPECIALISTS (/) Manchester (/) ENGLAND.
William Henry Fowler (1853–1932) and his son, Harold Fowler, took out several British patents for improvements to circular calculators between 1910 and 1924. The first Fowler calculator with two knobs on the rim was patented in 1914. In 1927, Fowler & Co. introduced the Magnum Long Scale Calculator, which extended the scale length to 50 inches. Thus, this example is dated between 1914 and 1927.
Charles Looney (1906–1987), the donor of this slide rule, catalogued engineering drawings and trade literature at the Smithsonian after he retired from the University of Maryland–College Park, where he served as chair of the Department of Civil Engineering. He also donated his library of books and pamphlets to the Museum.
References: Peter M. Hopp, "Pocket-Watch Slide Rules," Journal of the Oughtred Society 8, no. 2 (1999): 45–51; Richard Blankenhorn and Robert De Cesaris, "The Fowler Calculators: A Catalogue Raisonné," Journal of the Oughtred Society 11, no. 2 (2002): 3–11; Museum of History and Science in Manchester, "Fowler & Co.," http://www.mosi.org.uk/media/33870536/fowlerandco.pdf; accession file.
Location
Currently not on view
date made
1914-1927
maker
Fowler & Co.
ID Number
MA.333849
catalog number
333849
accession number
303780

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