'Pyroversum' (Temperature Indicator), 1920-1930
1920-1930
'Pyromite' Extinction Pyrometer (Optical Temperature Indicator), 1913-1958
1913-1958
'Wedge' (Temperature Indicator), 1913-1930
1913-1930
Optical Extinction Pyrometer (Temperature Indicator), 1875-1900
1846-1851
Optical Polarising Pyrometer
1900-1919
Stereo optical pyrometer
1901-1958
I-Rite Optical Pyrometer, 1900-1939
1900-1939