Holograph.
The delivery address on the envelope is: Mrs. Maria Weston Chapman, Summer St., Boston, U.S. It is postmarked Glasgow, No[v]. 17, 1846.
See Call No. Ms.A.9.2 v.22, p.131 for the letter by Catherine Paton to Maria Weston Chapman, Nov. 17, 1846, that was originally enclosed inside this envelope.