The largest microscope by Belthle & Rexroth (Carl Kellner’s successors), signed “C.KELLNER IN WETZLAR /BELTHLE & REXROTH.”, stamped serial no. 478. Made of lacquered brass and black lacquered cast and turned iron. Four eyepieces (I-IV), five objective lenses (signed “Belthle & Rexroth” and numbered “0-4”), mirror, can be turned around optical axis, condenser disc under table. Original wooden case with table of lens combinations and matching serial number. “Mikroskop Nr. 478 v. Belthle”. Dimensions of case: 32 x 7.5 x 11.5 cm, table height of microscope: 10.2 cm.

Extremely rare item in fully original condition with typed instructions with handwritten corrections (dated 1853 and corrected to read 1857) signed “Belthle & Rexroth”. Carl Kellner (1826-1855) founded the Optical Institute in Wetzlar together with Moritz Hensoldt in 1849. However, in 1854 Kellner contracted intestinal tuberculosis. Starting in December 1856, Friedrich Belthle (1829-1869), a former apprentice of this workshop, takes over the company after marrying Kellner’s widow (who had given birth to an illegitimate child of Belthle’s in August 1856 already). Belthle heads the young company, with Heinrich Friedrich Rexroth as a partner from August 1957 onwards. Ernst Leitz (1843-1920) joined the “Optical Institute” in Wetzlar in 1864 and became its sole owner in 1869. Leitz’ knowledge of serial production, which gave him an advantage over his competition, and the increasing demand for microscopes due to medical research were advantageous for the company’s rise.

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