CD’s letter concerning income tax on his US investments has not been found. A funded loan makes certain debts or stocks part of the permanent debt of the state, with provision for the regular payment of interest; a coupon is one of a set of certificates attached to a bond running for a term of years, to be detached and presented as successive payments of interest become due to the holder (OED). In 1877–8, the United States converted 6 and 5 per cent bonds into a funded loan for $739,000,000 (Palgrave ed. 1915, 1: 406). On 4 July 1878, CD recorded the receipt of £60 9s. 4d. from ‘Pensylvania R.’, presumably from the sale of the coupons; he had first purchased bonds in the Pennsylvania Central Railway in 1852 (CD’s Account books–cash account; CD’s Investment book (Down House MSS)). On 20 August, CD recorded the receipt of £94 12s. 6d. from the Boston and Albany Railway, which had been called the Western Railroad of Massachusetts when CD bought shares in it in 1852 (ibid.).