This might be N. D. Cotton, artist supplies, 7 Tremont St.
Balch's
William Y. Balch was a framer and art dealer in Boston whose store was on Tremont Row, located between the Tremont Temple and Gleason's Publishing Hall.
Thomas Hewes Hinckley
Thomas Hewes Hinckley (1813-1896), a well-known painter from Milton, MA.