Identified on the album page as the 'Hon.ble Lewis Grant (of Grant)', given the context of the album, this is probably the Hon. Lewis Alexander Ogilvy-Grant. Born on 18 September 1820, he was one of the younger sons of Colonel Francis William Ogilvy-Grant, 6th Earl of Seafield, and his first wife, Mary Anne Dunn.
The carte-de-visite comes from an album compiled by the sitter's step-mother, his father's second wife, Louisa Emma née Maunsell (later the wife of Major Godfrey Massy and then of Lord Henry Loftus). Not only was the Countess of Seafield his step-mother, she was also his sister-in-law, through his own marriage to her sister, Georgina. Put another way, in 1843 Louisa Maunsell married the 6th Earl of Seafield, who was some 46 years older than her. Six years later, in 1849, one of her step-sons married her sister, Georgina, thus becoming her brother-in-law too.
The Honourable Lewis Ogilvy-Grant gained the rank of Lieutenant in the service of the Royal Horse Guards. He died on 24 December 1902 at the age of 82.
Photographed by Stuart of Inverness.