Charpentier Calculator - Calculimetre G. Charpentier
Calculimetre G. Charpentier (obverse) Brevete S.G.D.G circa 1882
The Charpentier is a beautiful example of a circular slide rule dating from approximately 1882. A nickel plated metal body with a log scale along its outer diameter holds a brass inner ring also stamped with a log scale that rotates along with the cursor arm. The forked pointer is fixed to the brass ring via rivets and thus also rotates with the cursor arm.
Calculimetre G. Charpentier (reverse) Brevete S.G.D.G circa 1882
Calculimetre G. Charpentier Brevete S.G.D.G circa 1882
Though Charpentier is French for 'carpenter', this rule was not necessarily intended for tradesmen, rather the inventor was Monsieur G. Charpentier.
British Patent 2119 was provisionally granted in 1882 to A. J. Boult for G. Charpentier with the title "Slide Rule and Computing Scale."
Here is a nice photo of another example:
In some instances, the calculimetre is also stamped with the mark of Keuffel & Esser Co. of New York and Chicago, and K&E acted as an importing agent and distributor. Below is a reference from the 1895 Keuffel & Esser catalog
1895 Keuffel & Esser Catalog pg 185
The above is a line drawing (strikingly similar to that in the K&E catalog shown above), apparently from a work circa 1899, referenced in Cajori's History of the Logarithmic Slide Rule, which can be found here: sliderules.info/pdf/cajori.pdf
An excerpt from the Journal of the Oughtred Society Vol 0 No. 0 1991
which includes this interesting 3 page article by the inimitable Bob Otnes
Back issues of the Society's journals are available to members
Advertisement for the Charpentier Calculim�tre Cercle a Calcul
Emile David Maison 1901 (advert rearranged -- see source: reglasdecalculo.com)
From the 1889 Proceedings of the Royal Society of Victoria
Above and below is a most unusual Charpentier in its original case
Here the forked pointer of the classic Charpentier is replaced by a solid radial cursor attached
to the fob, and this cursor has a single rivet attachment to the brass inner ring.
The reverse has a stubbed radial cursor attached to the fob.
The diameter of this unusual piece is the standard size of 6cm.
The original case (source ebay.fr)
Calculimetre G. Charpentier with circular case
Fabriqu� par la maison TAVERNIER-GRAVET 19 rue Mayet � Paris
Operating instructions - in French - are here (posted by G. Martin of PhotoCalcul) An obverse/reverse photo from rekeninstrumenten.nl..