
Thermocouple Potentiometer (Electrical Resistance Meter), 1928
1928
1928
1889
1900-1918
1946
1910
1893
1966
1930-1960
circa 1940s-circa 1950s
circa 1940s-circa 1950s
1940
1897
circa 1925
1960-1969
1931
1950-1959
1957
1954-1974
1940-1959
1900-1920
1890-1900
1953
1900
1955-1964
1971
circa 1953
circa 1947
1960-1979