The consist of logs, 1779 to 1780, 1788 to 1790, 1793 to 1796, 1799 to 1802 and 1814. There is a collection of ship's books for La Seine, which includes a surgeon's journal kept by John Martin, 1799 to 1800. There are also letterbooks, 1804 to 1807 and 1808 to 1815. For the period of the North American command there is an out letterbook and order book, 1816 to 1819, and as Commander-in-Chief, Plymouth, a standing order book, 1842 to 1843. In addition, there are a large number of letters concerning prizes, 1799, letters received, 1819 to 1842, and drafts of letters to Lord Melville (q.v.), 1819, and Lord Dalhousie (1770-1838), 1818 to 1819. A number of documents with no immediate connection with Milne are also in the collection. They include the log of the Prince George, Captain Nathaniel Portlock, 1785 to 1787, on a voyage to the North Pacific; the log of the Africa, Alexander Purvis, 1793 to 1796, and the log of the United States privateer, Harlequin, 1814.

Administrative / biographical background
Milne entered the Navy in 1779 and served in the Canada until the end of the American War in the Channel and the West Indies. During the peace he was employed in merchant ships, among them the East Indiaman, General Eliott, 1788 to 1790. At the out-break of war, 1793, he went in the Boyne to the West Indies and subsequently joined the Blanche, in which ship he earned promotion to lieutenant for capturing La Pique in 1794. He became commander and captain in 1795 and was appointed to the command of La Pique in 1796. After two years service in the West Indies and the Channel, Milne, whilst taking La Seine, lost La Pique in action off Brittany and returned to the West Indies in La Seine. On renewal of the war in 1803, he was Commander-in-Chief at Leith until 1808, after which he had a period ashore in command of the Sea Fencibles. He was then appointed to the Channel Fleet in the Impetueux, 1811 to 1812, and to the Venerable, 1812 to 1813. From 1813 to 1814, when he became a rear-admiral, he was in North America in the Bulwark. Milne was Commander-in-Chief of the Halifax Station, 1816 to 1819, but before he departed, served as second-in-command to Lord Exmouth (q.v.) at the battle of Algiers, 1816. He was made a vice-admiral in 1825 and an admiral in 1841. His only further service was as Commander-in-Chief, Plymouth, 1842 to 1845, and he died during his journey home to Scotland.