F type hygrostat, c1935
1935
1935
1860
1977
1930-1935
1979
1890-1918
1935
2021
2022
1860
1961
1895
1900
1960
1895-1905
1962
circa 1961
1780
1964-1967
1900
1918
1859
1964-1967
1964-1967
1964-1967
1964-1967
1964-1967
1850
1880