
High frequency (violet ray) apparatus, 1950-1960
1950-1960
1950-1960
1950-1920
1957
1950
1960
1950-1960
1960
1960
circa 1960
2000-500
2000-800
1950-1959
1959-1960
1950-1959
circa 1950
1960
circa 1950
1953
1951
1951
circa 1960
1960
1955
1958
1971-1900
1960
circa 1960
circa 1960
circa 1960
1955
1952-1953
1952
circa 1950
1952
1957
1960
1956
1951
1953
1950
1951
1950
1950-1959
1953
1950-1960
1956
1955
1958
c.1952
1950-1959