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Credit
Specification of Arnold Hirst Watkins : respirators. Public Domain Mark. Source: Wellcome Collection.
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Public Domain Mark
You can use this work for any purpose without restriction under copyright law. Read more about this licence.
Credit
Specification of Arnold Hirst Watkins : respirators. Public Domain Mark. Source: Wellcome Collection.
Patent for "an improved respirator to be used in confined positions rendered unhealthy from the presence of noxious gases or effluvia"
Location | Status | Access | |
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Closed stores Pat. vol. 33 |
Location | Access | ||
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Closed stores Pat. vol. 33:8 |