Tuning forks of this type are used in audiology to ases the extent of any hearing los. These examples are; (1-4) described left to right. (1) c 1851-1895, made by Arnold and Sons, England. (2) c 1841-1920, English? (3) c 1901-1930, posibly of Brown's type, but was the personal relic of F T Burkitt. It was made by Lewis of London. (4) c 1874-1900, made by Down Bros, England.
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