Watercolour of Dr Duncan Stewart by Charles Grant.

Dr Duncan Stewart was the eldest brother of Margaret Brodie Herschel (nee Stewart) who in turn was married to John F.W. Herschel. Duncan was in India between 1825 and 1855 working for the East India Company as a medical doctor and it was during this period that this watercolour was created.

The date of the portrait suggests that it must have been by the politician Charles Grant, though his connection with the family is unknown. Charles' father, Charles Grant, director of the East India Company did have a documented relationship with the Stewart family. Charles Grant senior, an associate of Duncan's mother, was responsible for securing Duncan's appointment in the East India Company.