![](https://coimages.sciencemuseumgroup.org.uk/73/973/large_thumbnail_1923_0159__0001_.jpg)
Reason slot meter, c.1920.
1918-1922
1918-1922
1992
1945-1955
1950-1960
1960-1965
1973
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1900-1939
1960
1930-1950
1953
1977
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1970-1975
1965
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1875
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1920
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1979