I believe we actually have two Harrison Purser's. One belonged to "my" Ingram Purser, brother of Frederick Purser. Ingram Purser'sHarrison was born abt. 1843. Frederick Purser also had a son Harrison and a son Ingram.
Tom Purser has been a great source of information and posts frequently on the Purser Boards. He mentioned that the mother of Frederick, Ingram, Charles and Henry was Ann(ie) Ingram....which explains the frequency of the Ingram name along with the Purser surname.