Fuller's Computing Telegraph Circular Slide Rule

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.
Currently not on view
Object Name
calculating rule with case
slide rule with case
date made
George Philip and Son
Physical Description
paper (overall material)
overall: 1.4 cm x 28.7 cm x 28.3 cm; 9/16 in x 11 5/16 in x 11 5/32 in
place made
United Kingdom: England, London
ID Number
catalog number
accession number
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History, Kenneth E. Behring Center


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