Laboratory standard a.c. and d.c. (electrodynamometer) voltmeter with 12 inch scale
1952
1952
1949-05-06
1949-05-06
1941
1955
1964
1985
1953
1950-1960
1949-05-06
1949-05-06
1949-05-06
1964-01-21
1949
circa 1919
1959
1930
1955-1960
circa 1955
1950
1912-1920
1919
circa 1971
1955
1953
1948-05-05
1921-1930