
Laboratory standard a.c. and d.c. (electrodynamometer) voltmeter with 12 inch scale
1952
1952
1955
1949-05-06
1941
1949-05-06
24 February 1951
circa 1946
circa 1960
1964
1985
1950-1960
1953
1949-05-06
1949-05-06
1949-05-06
1964-01-21
1930
1949
1950
circa 1954
circa 1955
circa 1919
1955-1960
1953
circa 1971
1955
1912-1920
1948-05-05
1921-1930
1919
1949