Adelaide C. Okell was a concert pianist who lived in New York City.  She studied piano under Madame Teresa Carreno, a world famous pianist in the 19th and 20th centuries. In the summer of 1898, Okell took a trip to Europe.  In 1917, she lived on West 84th Street and was employed as a pianist.

Sources: 

General & Business Directory of the Boroughs of Manhattan & Bronx City of New York, 1917

E-mail from Karen Sinunu to Curt Hanson, Elwyn B. Robinson Department of Special Collections, July 2011