The papers consist of eighteen diaries, 1880 to 1897, 1890 and 1895 excepted, which describe all the major events of Johnstone's life in detail. His logs cover the years 1858 to 1864, 1866 to 1867 and 1871 to 1873. There are official letters among the loose papers, as well as letterbooks, 1883, 1892 to 1894, 1896 to 1898, and many of these refer to Madagascar and to the collision between HMS VICTORIA and HMS CAMPERDOWN. For the latter affair, there is Johnstone's own vindication of his conduct. The printed papers, including newspaper cuttings, relate to events in Borneo and Madagascar, and to the education of naval officers.

Administrative / biographical background
Johnstone was born in 1843 and entered the Navy in 1858. As a midshipman he served in HMS MARLBOROUGH in the Mediterranean, then in HMS ST. GEORGE. He was promoted to lieutenant in 1865. From this time until 1873 he served on the China Station in HMS SERPENT, HMS PERSEUS and HMS JUNO, and was then appointed to the command of the training brig HMS LIBERTY. After being promoted to the rank of commander in 1877, he commanded HMS EGERIA in China and the wooden sloop HMS DRYAD in the East Indies. During these two appointments he was involved in diplomatic affairs in Borneo and then in Madagascar, services for which he was promoted to captain in 1883. In the following year he was awarded the gold medal of the Royal United Service Institute for an essay on the organisation of naval personnel during wartime. He attended the Royal Naval College, Greenwich, and subsequently served on a committee inquiring into the education of naval executive officers. From 1885 to 1889 he commanded HMS VOLAGE in the Training Squadron. In 1891 he took command of the battleship HMS AGAMEMNON and turned over with his crew to HMS CAMPERDOWN the following year. He was still in command of the CAMPERDOWN when she collided with HMS VICTORIA off the coast of Tripoli in 1893, an incident for which he was held partly to blame by the Admiralty. Johnstone's only further appointment before retirement was as captain of the naval barracks at Devonport, 1896 to 1898. He was promoted to rear-admiral in 1899 and vice-admiral in 1903. He died at Ruthwell in Dumfriesshire in 1927.