The date range is established by the change of Erasmus’s house number from 37 to 6 Queen Anne Street in early 1860 (Post Office London directory), and by the dates when CD entered his annual ‘Tithes’ in his Account books (see n.2, below); after 1868, they were entered in months other than November (except in 1871, when CD entered them on 29 November).
In his Account and Investment books (Down House MSS), CD referred to an annual income ranging in the 1860s from £15 to £21 as the ‘Castle Morton Tithes’. CD and each of his five siblings inherited one sixth of a ‘Castle Morton trust’ from their father, Robert Waring Darwin, in 1837. The trust was evidently related to a property of CD’s grandfather, Josiah Wedgwood I, in the parish of Castle Morton, Worcestershire. (Robert Waring Darwin’s Investment book, Down House MS.)