Laboratory standard a.c. and d.c. (electrodynamometer) voltmeter with 12 inch scale
1952
1952
1955
1941
1949-05-06
1949-05-06
1964
24 February 1951
1985
circa 1946
circa 1960
1950-1960
1953
1959
1949
1949-05-06
1949-05-06
circa 1919
circa 1954
1955-1960
1964-01-21
1930
1949-05-06
1950
circa 1955
1912-1920
1919
circa 1971
1953
1955
1948-05-05
1949
1921-1930