A double full-length portrait showing Captain Bentinck seated on the left in captain's full-dress uniform, over three years, 1774-87, and a grey wig with a gold signet ring on his little finger. His son William, who was 11 years old when this portrait was painted, stands facing towards his father in the uniform of the Naval Academy at Portsmouth. Under his arm, William cradles an incomplete model yacht, from which the boom and sails are missing. He holds a loose rope from model’s rigging in his right hand, the implication being that he is learning about the principles of ship design through the construction of the miniature vessel. Captain Bentinck inclines his head towards the boy and gestures with his left hand in a manner that suggests instruction. They are shown in a captain’s cabin, probably intended to represent the cabin of the ‘Centaur’, 74 guns, which Bentinck commanded between 1770 and 1773 when it was the guardship at Portsmouth. There is a bell-pull for summoning attendants on the left and two guns are suspended from the far wall above an upholstered bench, upon which lies a discarded sword. On a table to the left, John Bentinck's right arm rests on a pile of books, including volumes inscribed ‘Anson’s Voyage’ (referring to the official account of Admiral George Anson’s circumnavigation, published in 1748) and ‘Saunderson’s Algebra Vol. 1’ (referring to Nicholas Saunderson’s ‘The Elements of Algebra, in Ten Books’, first published in 1740). Underneath this pile is a diagram for an improved chain pump designed by Captain Bentinck, who invented many new naval technologies. This diagram was apparently copied by the artist from the captain’s ‘Scheme Book’, in which he recorded his inventions; an eighteenth-century copy of the Scheme Book is preserved in the Caird Archive at the National Maritime Museum (see SPB/33). Inscribed ‘Memorandums relative to the Capstan 1770’, the rolled paper in Bentinck’s right hand also refers to a document in the Scheme Book. This memorandum described a new design for ships’ capstans, a model for which is depicted on top of the bureau in the portrait’s background. The pulley block lying on the deck beneath the table provides another reference to one of Bentinck’s inventions. The portrait thus emphasises Bentinck’s mastery of the technical aspects of his profession, knowledge which he seems to be passing on to his son. The interaction between father and son also creates an atmosphere of intimacy and domesticity within the painting, which is reinforced by the captain’s relaxed pose and by the presence of the sleeping spaniel in the lower left. Captain Bentinck perhaps knew the artist, Chamberlin, through the American inventor and politician Benjamin Franklin, with whom Bentinck collaborated on a series of scientific experiments at sea in 1773. Franklin had been painted by Chamberlin in 1762 (this portrait is now in the Philadelphia Museum of Art) and may have recommended the painter to the naval captain. The son of a Dutch nobleman, Captain Bentinck was a highly learned man and corresponded with the French philosopher Jean-Jacques Rousseau. Signed by the artist and dated ‘1775’, the portrait was produced shortly before the captain’s death from a sudden illness in September 1775 at the age of thirty-seven, leaving a widow and seven young children. After his death, Captain Bentinck was praised by the Reverend James Fordyce in his ‘Addresses to Young Men’ (1777) as ‘a man who possessed the masculine character in an uncommon degree: but, what rendered it peculiarly interesting, it was adorned by much knowledge and many liberal acquirements, illuminated by a large share of sentiment, as well as vivacity, and tempered with the happiest domestic affection.’ His son William later became a naval captain and the National Maritime Museum also has his portrait by George Romney (see BHC2551). (Updated April 2019.)