;Classical and renaissance artwork Greville lived most of his adult life on a rigid income of ₤500 a year, generated from landowning and investments, with which managed to acquire antiquities from Gavin Hamilton in Rome. He also purchased through his uncle a genre piece by Annibale Carracci. Greville was the nephew of Sir William Hamilton, the British envoy at Naples who formed two collections of Greek vases, one of which is at the British Museum. ;Stones and minerals As a Fellow of the Royal Society, his special interest was in minerals and precious stones, which were catalogued by the émigré Jacques Louis, Comte de Bournon and were later purchased via Act of Parliament for the British Museum. He was good friends with James Smithson, whom he sponsored for membership in the Royal Society and with whom he exchanged minerals. ;Horticulture Greville remained for years a very close friend of Sir Joseph Banks and, like him, a member of the Society of Dilettanti. He accompanied Banks at the organizing meeting in March 1804 of the precursor to the Royal Horticultural Society, the Society for the Improvement of Horticulture. ;Portraits of Emma Hart Greville gave Amy Lyon the name of Mrs Emma Hart when he took her as mistress in 1782. He helped to educate her, and took her to George Romney's studio, where he was sitting for his own portrait. Romney became fascinated with the beautiful Emma, and painted allegorical "fancy pictures" of Emma in various guises forty-five times.
The construction of the seaport of Milford Haven, Pembrokeshire, South Wales, is due to Greville's entrepreneurial spirit. When it was the property of Sir William Hamilton, Greville applied for an Act of Parliament to enable Hamilton and his heirs to make docks, construct quays, establish markets, with roads and avenues to the port, to regulate the police, and make the place a station for conveying the mails. The first structure was a coaching inn. Quaker whaling ship owners from Nantucket were induced to settle, and for some decades Milford was a whaling port. A royal dockyard was established during the Napoleonic Wars. At his death in 1803, Hamilton bequeathed it to his nephew. At a site on high ground in nearby Hakin, Greville planned to build the College of King George the Third to allow the study of mathematics and navigation, whose centrepiece would be an observatory. Although the observatory was built, and scientific instruments delivered, the college never functioned as such as after the death of Greville in 1809 the whole project was abandoned.
Personal life
Greville never married, but had a liaison with Emma Hamilton for several years when she begged for his help after becoming pregnant with Sir Harry Fetherstonhaugh's child in 1782 and he rejected her. Greville took her in on condition that the child, Emma Carew, was fostered out, and Emma Hamilton became his mistress. He later helped to engineer her meeting and subsequent marriage to his uncle Sir William Hamilton, perhaps in an attempt to win his favour and also to clear the way for him to finding a wealthy wife. He lived for years in a house he had built facing Paddington Green, then a village on the outskirts of London, not far from the house in which he had installed Emma and her mother. He kept Romney's paintings of Emma on the walls of his house until his death. There he indulged his passion for gardening in a large garden provided with glasshouses in which he grew many rare tropical plants, aided by his connection with Banks, and managed to coax Vanilla planifolia to flower for the first time under glass, in the winter of 1806–07. His contributions to the herbarium assembled by Sir James Edward Smith are preserved by the Linnaean Society of London. The Australasian genusGrevillea is named in his honour. In the latter part of his life he lived at Warwick Castle. Greville died on 23 April 1809, aged 59.
Recognition
Grevillea, a diverse genus of about 360 species of evergreen flowering plants in the family Proteaceae, is named after him, due to his role as a patron of botany and co-founder of the Royal Horticultural Society. Greville Island, in the South Island of New Zealand, was named to honour his memory by Francis Barrallier, in 1820. Greville plays a role in Susan Sontag's 1992 novelThe Volcano Lover, about Sir William Hamilton.
