This is issue 4 of the Palmer’s Computing Scale and bearing the inscription “Improved by Fuller” on one side. The original patent date was 1843 entered by Aaron Palmer of the clerks Office, Boston Mass.. But the Patent was purchased by Professor Fuller and improved by him. The Computing Scale bears scales for percentages, monetary transactions and interest.

Fuller’s Time Telegraph on the other side has a patent date of 1845, Boston, Mass. It enables the calculation of the number of days, weeks, or months to be determined between two given dates without calculations.

The scale is described by Hook and Norman1 as:

Palmer and the engraver George Smith began working on their design for an “endless computing scale” in early 1841. It was copyrighted in Boston in late 1843, and versions of the device continued to be produced until at least 1852. Palmer’s slide rule enjoyed only a limited success, largely because of poor marketing and the American public’s fear that use of the device “[would] tend to weaken the mind, by causing it to rely upon mere mechanism to make its numbered computations”2.

The instrument is engraved volvelle (by George G. Smith) mounted on heavy cardboard with edges bound with gilt leather strips and is 11” square. It represents one of the earliest applications of the words “computing” to an instrument. At the time a computer usually referred to a person employed to do calculation.

Condition is good with the leather bound sides only slightly marred and the red still bright. The metal control hole is slightly tarnished. The circular scales both move freely. Whilst there is some discoloration to the faces every number and all instructions printed on both sides are very readable.

In 1909 Florian Cajori3 described the components from which this instrument was developed as follows:

80. J. Fuller’s Computing Telegraph.

[This instrument consists of a “Time Telegraph,” de-signed by Fuller, which he added to or united with Aaron Palmer’s “Computing Scale.” The “Time Telegraph” was a non-logarithmic circular scale for determining the number of days between given dates. See Improvement to Palmer’s Endless Self-Computing Scale and Key; with a Time Telegraph, making, by uniting the two, a Computing Telegraph. By John E. Fuller, New York, 1846. See also the Colorado College Publication, Engineering Series, Vol. I, No. 7 (1909).]

81. J. Fuller’s Telegraph Computer.

[Telegraphic Computer, a most wonderful and extraordinary instrument, by which business questions, of every possible variety, are instantly performed; a safe and speedy check to avoid vexatious errors, affording at the same time a greater amount of practical business knowledge than can be obtained for ten times the cost of this work. Sold only by subscription. John Fuller, New York (about 1860). Cited by Favaro, op. cit., p. 510. A circular slide rule.]



1 Diana H. Hook and Jeremy M. Norman, Origins of Cyberspace: : A Library on the History of Computing and Computer-Related Telecommunications, Norman Publishing, 2002, pp. 269–70. (↑)

2 see Fuller, Key to Palmer’s Computing Scale, 1846, above. (↑)

3 Florian Cajori, The History of the Logarithmic Slide Rule, Engineering news publishing Company, USA, 1909, p. 47. (↑)

Pages linked to this page

Creative Commons License This work by Jim Falk is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License Click on the logo to the left to see the terms on which you can use it.

Page last modified on 11 May 2014