Clinometer patent by C. A. Schmalcalder, 82 Strand, London, England, 1810-1826. Patent clinometer, British, 1810-1826 1810-1826
Screwbarrel and aquatic microscope in fishskin case, by Dollond, London, 1761-1780 Screwbarrel and aquatic microscope in fishskin case 1761-1780