Aviation Barograph by Jules Richard, Paris. Aviation Barograph by Jules Richard, Paris. Aeronautics 1900-1915
Eye-piece micrometer inscribed E.6 in wood mount with brass frame divided circle (120 divisions numbered from 0 degree to 60 degrees) and steel screw, 2 threads in position Filar micrometer by William Herschel, 1780-1800 Astronomy 1780-1800