 In 1906, she was one of the charter members of the Welsh Folk-Song Society (Cymdeithas Alawon Gwerin), and in 1930 she was elected to a term as president of the society.She and other Society members collected wax cylinder recordings of Welsh-language traditional songs, and published a journal of their findings.Books authored by Ruth Herbert Lewis include "Folk-Songs Collected in Flintshire and the Vale of Clwyd" (1914) and "Second Collection of Welsh Folk-Songs Collected by Lady Herbert Lewis" (1934).