
Filings coherer, glass tube formed into bulbs at each end at right angles, 1899
1899
1899
1895-1906
1898
1890-1897
1898
1894
1894-1904
1894-1904
1900-1920
1898
1894-1904
1900-1910
1894
1894-1904
1902
1889
1908
1904
1885-1895
1880-1920
1914-1918
1880-1915
1901-1916
1880-1920
1914-1918
1900-1916
1881-1900
1900-1913
1904
1900
1914
1880-1920
1880-1910
1900-1914
1901-1920
1914-1918
1880-1919
1900-1920
1880-1910
1880-1920
1901-1905
1915-1918
1890-1900
1914-1918
1913-1923
1880-1920
1880-1920
circa 1919
1895-1905
1900-1920