Improvements in apparatus for generating and applying fumes, smoke or vapours for disinfecting, deodorizing or fumigating purposes, or for the testing of pipes or passages by what is known as the smoke test, or for analogous purposes / [John Watts].

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Improvements in apparatus for generating and applying fumes, smoke or vapours for disinfecting, deodorizing or fumigating purposes, or for the testing of pipes or passages by what is known as the smoke test, or for analogous purposes / [John Watts]. Public Domain Mark. Source: Wellcome Collection.