[1] Adam was the second son of Alexander Duncan, Baron of Lundie, Angus, (d. May 1777) Provost of Dundee, and his wife (and first cousin once removed) Helen, daughter of John Haldane of Gleneagles.

[1] During this time, he lived principally at Dundee, and married Henrietta, daughter of Robert Dundas of Arniston, Lord President of the Court of Session on 6 June 1777.

[1] During the summer of 1779, Monarch was attached to the Channel fleet under Sir Charles Hardy; in December was one of the squadrons with which Rodney sailed for the relief of Gibraltar, and had a prominent share in the action off St. Vincent on 16 January 1780.

[3] During the first two years of Duncan's command, the work was limited to enforcing a rigid blockade of the enemy's coast, but in the spring of 1797, it became more important from the knowledge that the Dutch fleet in the Texel was getting ready for sea.

[5] For political purposes, however, the French Revolutionaries who controlled the government in Holland (despite the contrary opinion of their admiral, De Winter), ordered him to put to sea in the early days of October.

[4] Duncan, with the main body of the fleet, was at the time lying at Great Yarmouth revictualling, the Texel being watched by a small squadron under Captain Henry Trollope in HMS Russell, from whom he received early information of the Dutch being at sea.

He at once weighed anchor, and with a fair wind approached the Dutch coast, saw that the fleet was not returned to the Texel, and steering towards the south sighted it on the morning of 11 October about seven miles from the shore and nearly halfway between the villages of Egmont and Camperdown.

At first, he was anxious to bring up his fleet in a compact body, for his numbers were at best equal to those of the Dutch; but seeing the absolute necessity of immediate action, without waiting for the ships astern to come up, without waiting to form line of battle, and with the fleet in very irregular order of sailing, in two groups, led respectively by himself in Venerable and Vice-admiral Richard Onslow in Monarch, he made the signal to pass through the enemy's line and engage to leeward.

[4] It was a bold departure from the absolute rule laid down in the Fighting Instructions, still new, though warranted by the more formal example of Howe on 1 June 1794; and on this occasion, as on the former, it was crowned with complete success.

[4] It had been proposed to De Winter to make up for the want of skill by firing shell from the lower deck guns, and some experiments had been made during the summer which showed that the idea was feasible.

Even as early as 18 October his aunt, Lady Mary Duncan, wrote to Henry Dundas, at that time secretary of state for war: Report says my nephew is only made a Viscount.

Three years later, 4 August 1804, he died quite suddenly, aged seventy-three, at the inn at Cornhill, a village on the border, where he had stopped for the night on his journey to Edinburgh (ib.

The paternal arms of the 1st Viscount were: Gules, two cinquefoils in chief and a bugle horn in base argent stringed azure (Clan Duncan).

[16] In the centre of his paternal coat the 1st Viscount was granted an augmentation of honour: Pendant by a ribbon argent and azure from a naval crown or a gold medal thereon two figures the emblems of Victory and Britannia; Victory alighting on the prow of an antique vessel, crowning Britannia with a wreath of laurel; and below the word "Camperdown" Crest: A first rate ship of war, with masts broken, rigging torn and in disorder, floating on the sea, all proper and over, the motto "Disce Pati" ("learn to suffer").