An interesting set of two conversion rules/rulers offered by a father to his son with the engraved sentence : “Chalicarne à son fils / henri Gabriel / 1861″ [Chalicarne to his son Henri Grabril” and dated “1861”]. The other rule is engraved “Chalicarne à Eclaron”.
The dedicated rule is made in silvered steel and is engraved with four conversation tables : 1/500, 1/1000, 1/1600 and 1/2000. It measures 22,9×6,1 cm.
The second rule is made in full brass and is engraved with four conversion tables : 1/500, 1/1000 and 1/800, 1/400. It measures 27,5×6,1cm.
Both are preserved in their original leather case.
Eclaron is a city in the East of France. We cannot find any information about an engineer or mechanic in this city around 1850/1860, named Chalicarne.
The silvering, which seems to have been made not professionnaly, left some masses of silver on the ruler.
A quite unusual set of ingineering conversion rules.
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Established by Alexandre Piffault in 2014 and based in Paris at 5 rue de Condé, 75006, very close to Odéon, Le Zograscope specializes in antique and rare books in Science, Medicine and Technology, and rare antique instruments in the same fields. We have especially a strong interest in early and continental microscopy, early and special mathematical/drawing instruments, medical and surgical instrument, and rare technology.