Large Gelinski Calculator By Bianchi, C. 1850

Gelinski graphite calculator signed on the instrument "Bianchi in Paris and Toulouse", dating back to around 1850. Charles Frédéric Gelinski is a Polish nobleman originally from Vilnius, born August 10, 1771, engaged in the Austrian army, he was made 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. This rare instrument is made of brass, copper, glass and ebony. It makes it possible to use the so-called graphic method in surveying for the rapid construction of the most complex polygons: "This instrument gives very quickly and with rigorous accuracy the content of the most irregular figure". The instrument was invented around 1815 according to a publication published by Veuve Bizette, "Description of M. Gelinsky's Calculator, and manner of using it", then regularly promoted in surveying manuals until the beginning of the 1840s. Rare large copy bearing Bianchi's late signature. The instrument dates back to around 1850. In comparison to the original Richer model, an ebony ruler and a locking screw were added to this Bianchi model when using the glass ruler. The last photo gives a comparison between the two instruments Richer and Bianchi. The instrument measures 37x10 cm.