The letters include the correspondence of Major-General John Brown, Royal Staff Corps, uncle of Sir George, regarding engineering works in Ireland and the false report of his nephew George's death at Bladensburg, 1789-1814; and a report on the Moray floods, compiled in 1829 by Peter Brown for Sir Thomas Dick Lauder's ‘Account of the Great Floods’ (Edinburgh, 1830) (MS.1847).

The correspondence of Sir George Brown relates, among other things, to Army administration at the Horse Guards, 1843-1853 (MSS.1847-1848), to the Crimean War, and to military affairs in Ireland, where he was Commander-in-Chief, 1861-1865 (MS.1854). The Crimean papers include his correspondence on the field of operations, from 1854 until he was invalided home in June, 1855 (MSS.1849-1850), and letters written to him later by officers at the front, 1855-1856 (MSS.1851-1852). Discussion of the War, with criticism of Kinglake, continues into later years.