Charpentier Calculator - Calculimetre G. Charpentier

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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

 

  

 

 

 

 

 

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.

(source ebay.fr)

 

The reverse has a stubbed radial cursor attached to the fob.

The diameter of this unusual piece is the standard size of 6cm.

(source ebay.fr)

The original case (source ebay.fr)

 

 

 

Links   

 

Operating instructions - in French - are here (posted by G. Martin of PhotoCalcul)

Rod Lovett has some nice Charpentier calculator photos and some additional details
Giovanni Breda has some good photos/details for the Charpentier (here is just the photo).
The reglasdecalculo.com site has old ads for the Charpentier and other circular slide rules.
The 1889 Proceedings of the Royal Society of Victoria has a few pages on the Calculimetre.
The mccoys-kecatalogs.com site has the Keuffel & Esser Co. model numbers for the Charpentier.
Gallery of very nice photos of slide rules and calculators PhotoCalcul (French Language).

An obverse/reverse photo from rekeninstrumenten.nl..