Clinometer patent by C. A. Schmalcalder, 82 Strand, London, England, 1810-1826. Patent clinometer, British, 1810-1826 1810-1826
Spring fleam, steel, in rayskin case, first improved pattern by John Weiss, 62 Strand, London, England, 1820-1825. Spring fleam 1820-1825