Joly block photometer, an optical demonstration instrument, unsigned, British, 1884-1946. Consists of two plocks of opal in wooden mount. Joly block photometer 1850-1950
Joly's original differential steam calorimeter for measuring specific heat of gases at constant volume, 1889. Including two of the original containing vessels for holding the gas under investigation Joly's Differential Steam Calorimeter, 1889 1889
Six examples (each 3/4" x 3 1/4") of Joly's colour process of photography. Mounted on viewing stand, with light tight curtain. Six examples (each 3/4" x 3 1/4") of Joly's colour process of photography
Original Joly colour photography outfit, comprising of: taking screen, 3 viewing screens and finished example, together with the original circulars and working instructions. Original Joly colour photography outfit