In 1845, two years after Aaron Palmer copyrighted the second
slide rule devised and made in America, John Emory Fuller
(1799-1878), copyrighted the third.
Palmer’s rule was a true logarithmic slide rule, with which
calculations could be made and for which numerous gauge points
were provided; but Fuller’s was purely arithmetical, and would
only provide the number of days between dates, and a rule, such
as Palmer’s, would be needed for any further calculations,
such as wages.
So, two years later, he wisely bought the copyright from Palmer
and, as they were approximately the same size, he placed the
instruments back to back; this appears to be his ‘improvement’,
and was probably a sensible commercial decision.
When Fuller added his own name to Palmer’s copyright notice,
the engraver failed to change the full stop to a comma:
‘Massachusetts. and by J.E.Fuller 1847’, the engraver used
the same device in the corners of each slide rule.
However, a circular elapsed-time slide rule was not novel, as a
similar instrument had been brought out in 1818 by a Scottish
accountant, Thomas Dunn; perhaps Fuller saw one of Dunn’s
slide rules and plagiarized it.
The instrument slips into a folder containing a book of instructions,
a sheet of American statistics (ca.1860) and a fold-out sheet of
mechanical powers (ca.1851).
Condition of the instrument is fair noting that one volvelle is slightly
warped, there is some scuffing to the corners and some slightly
loose passepartout. Overall size 11.3 inches (28.6cms) square.
American ca.1860. Ticket Price £550. Email me here.
See: A. Palmer, A Key to the Endless, Self-Computing Scale,
Showing its Application to the Different Rules of
Arithmetic &c, Boston Smith and Palmer 1844
A. Palmer, Palmer’s Pocket Scale with Rules for its Use
in Solving Arithmetical and Geometrical Problems.
Rochester Aaron Palmer 1845 Printer Caufield and Warren.
Preface dated: Boston Feb. 15, 1844
John E. Fuller, Improvement to Palmer’s Endless Self-
Computing Scale and Key .......... with a Time Telegraph,
Making, by Uniting the Two, a Computing Telegraph
New York 1846. (A photocopy is supplied with the rule)
For Dunn see: Bulletin of the Scientific Instrument Society,
No.3 1984, pp.5, 9 (A copy is also supplied)
Note: from the 18th. century, a computer was one who did
calculations, and this may be the first time it was used to refer to a
device rather than a person. The allusion to telegraphy was
because they were just starting to be introduced, and were
considered the technical marvel of the period.
