
Glass specific gravity hydrometer marked Townson & Mercer
1900-1960
1900-1960
1886
1886
1886
1897-1910
1885
1890
1900-1905
1900-1980
1900-1960
1900-1920
1951-1960
1900-1939
1910
1849
1870-1910
1886
1886
1897-1918
1900-1905
circa 1885
1912
1851-1900
circa 1900
1912
1918-1949
1900-1980
1950-1960
1890-1939
1900-1960
1900-1960
1885
1897-1918
1901-1914
1900-1960