This is a late but massive example of the rare Gelinski’s so called “calculateur graphite”, ei calculator or transformer graphic invented by Gelinski in 1815 and described in the French surveying textbooks untils 1840s’.
The present instrument is of massive size and built in brass, copper, glass and ebony, preserved in its original case. It is signed “Bianchi à Paris et à Toulouse”, datable circa 1850. For a comparison with the Richer example, see the last picture. The glass ruler is especially thick. A buttom was added and also a ebony handle.
Charles Frédéric Gelinski is a Polish-born from Vilnius, born August 10, 1771, engaged in the Austrian army, he was taken prisoner by the French. He subsequently remained in France and was admitted to the Ponts et Chaussées in Troyes, then, in 1812, in Holland, in the department of Friesland, then controlled by France. He was naturalized French by order of the king dated October 4, 1814.
The present ruler makes it possible to calculate surfaces on a plane by the graphic method, by transforming an irregular figure into a simpler shape, such as a triangle.
It was first described in 1815, then in 1830 in the Lecoy’s book Méthode simple et facile pour lever les plans, suivi d’un traité du nivellement et d’un abrégé des règles du lavis”, etc.
Size of the ruler : 37x10cm.
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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.
Personnal website : https://www.lezograscope.com/