Althorp Papers. Vol. mmdlxxxiv. 1. Letters and associated papers addressed to Beauchamp Seymour as Commander of H.M. Steam Sloop Cormorant; 1845-1847. 2. Beauchamp Seymour's account of his passage home with H.M.S. Cormorant through the Straits of Magellan; 1847.
Althorp Papers. Vol. mmdlxxxv. Letters and papers, mostly from Frere (solicitor), also two from Lord Spencer, relating to the East Molesey estate, Surrey; 1875-1876.
Althorp Papers. Vol. mmdlxxxviii. Letters to Adelaide from her brother Beauchamp; 1834-1864. For Adelaide's letters to Beauchamp Seymour, see Add. MS 77870.
Althorp Papers. Vols. mmdlxxxviii-mmdxcii. Letters relating to Adelaide Horatia Elizabeth Seymour, daughter of Sir Horace Seymour, and from 1854 the second wife of Frederick, 4th Earl Spencer; 1834-1860, n.d. Five volumes.
Althorp Papers. Vols. mmdlxxxix-mmdxci. Letters to Adelaide from her brother Charles; 1845-1854. For Adelaide's letters to Charles Seymour, see Add. MS 77853. Three volumes.