The difficulties of the landing at Port Louis, and the strength of the batteries by which it was defended, were such as to triumph over even the genius and courage of Boscawen; and after vain though most strenuous search for a practicable landing-place, the Admiral called a council of war, at which it was determined that a small boat-party should land during the night with a view to capturing (if possible) at least one man of the enemy, from whom they might obtain information as to the numbers and situation of the French forces. This ingenious attempt, however, failed; and at a second council of war it was agreed that the attack on Port Louis, even if it succeeded (which was doubtful), would necessitate the leaving behind so large a force to occupy the place, that it would imperil the chances of capturing Pondicherry, the principal object of the expedition; and to this it may be added that Boscawen had lost many of his men from their eating a poisonous fish called the vieille, at the island of Roderique.
They accordingly sailed at once for Fort St. David, near Pondicherry, which place they reached on the 29th July; and here Boscawen took over the command, from Admiral Griffin, of what had now become the largest 'marine force belonging to any one European nation that had ever been seen in the Indian seas.' Boscawen marched forward with his army on the 8th of August, and opened the trenches on the 27th. But his men rapidly grew sick in that unwholesome climate; his chief engineer was killed; the monsoons were shortly expected. It was found that the garrison far outnumbered the besiegers, and, 'everything having been done which gallantry and perseverance could perform,' writes Walpole, on the 6th October it was finally determined to raise the siege.[93] And a gale, on 14th April, 1749, arose, which seems to have been the main cause of the unsuccessful termination of the whole expedition—the Admiral's flag-ship, the Namur, foundered; the Pembroke and the Apollo (hospital ship) were also lost, together with a very large proportion of their crews. Providentially, our Admiral and General was on shore at the time.
Not long afterwards peace was declared at Aix-la-Chapelle, and Boscawen had, at least, the gratification of having Madras delivered up to him.
In April, 1750, he returned to England in the Exeter, to find that during his absence he had been appointed Rear-Admiral of the White; and additional honours soon after fell to his lot. In 1751 he was made a Lord Commissioner of the Admiralty, and at the Board's meetings found many opportunities of falling foul of his old foe, Anson, whom he always suspected, perhaps without sufficient cause, of having sent him on what the former knew from the beginning would be the fruitless expedition to Pondicherry. This suspicion, however, would seem to be confirmed by a letter from Walpole to Mann, dated 31st January, 1750, in which the writer says that Boscawen was unfortunate during the whole expedition (East Indies), and that Anson sent him upon it 'on purpose to ruin him ... upon slight intelligence, and upon improbable views.' A jealousy, as we have seen, had previously arisen between the two Admirals over the Cape Finisterre affair, when Boscawen complained loudly of Anson's behaviour. In July, 1751, he was made an Elder Brother of the Trinity House; and in May, 1754, he was, for the third time, chosen to represent in the House of Commons his old borough of Truro, between which and himself there had existed so long and friendly a connexion;—and now, 'for want of something better to do,' as one of his biographers insinuates, he became a zealous politician.
In 1755 he was made Vice-Admiral of the Blue; and, the French beginning to display ambitious projects in America, Boscawen was despatched from Spithead on 19th April, with a strong fleet, to frustrate their designs. The French Admiral was M. Bois de la Motte, and he had a large and powerful armament of twenty-five ships of the line, and other vessels, together with a train of artillery, etc., etc. Boscawen's force consisted of eleven sail and a frigate, together with two regiments of infantry. He was, however, afterwards reinforced by six ships of the line and another frigate under the command of Rear-Admiral Holbourne. The English ships waited for the Frenchmen off Cape Ray, Newfoundland; but in a fog the French Admiral eluded his antagonists, and contrived to get his ships (with two exceptions) into harbour. These two ships Boscawen captured on the 10th June, after a gallant engagement of five hours. They contained £80,000 in specie, a large number of French officers, and altogether 1,500 prisoners. The two French ships were the Alcide and Lys (each of 64 guns), which were taken by the Defiance and the Dunkirk. Again Boscawen took the first French ships during the war; and again found his old acquaintance, M. Hocquart, on board one of them, who thus for the third time became the British Admiral's prisoner of war. The story of the action is thus graphically told by Lord Mahon:
'Only the day before King George III. embarked at Harwich (for his usual summer residence at his beloved Hanover, notwithstanding the strong feeling which existed against his leaving the kingdom at so critical a time) Admiral Boscawen, with eleven ships of the line and two regiments on board, set sail from Portsmouth. His orders were to follow a large French armament which had recently been equipped at Brest, and to attack it if designed for the Bay of St. Lawrence. A thick fog off Newfoundland concealed the rival fleets from each other; but two English ships, the first commanded by Captain (afterwards Lord) Howe, came within speech of two French ships. The foreign commandant inquired if it was war or peace. Howe replied that he must wait for his Admiral's signal, but that he advised the Frenchman to prepare for war. Ere long appeared Boscawen's signal for engaging; Howe attacked, and after an engagement, in which he displayed equal skill and intrepidity, succeeded in taking the two French ships—the Alcide and the Lys. The rest of the French armament—eight or nine ships of the line—got safe into the harbour of Louisbourg; and their safety caused as great disappointment in England as the capture of their consorts irritation in France. The French Ambassador in London, M. de Mirepoix, was recalled at these tidings, yet still there was not on either side a formal declaration of war.'
On the 15th November, Boscawen returned to England with his prizes and his prisoners, and anchored at Spithead.
In the following year, 1756, he commanded the squadron in the Bay of Quiberon, stationed there for the purpose of watching the French fleet; but, so far as I am aware, was engaged in no important active service on that occasion. His leisure, however, gave him an opportunity of showing the interest he took in the welfare of his men, as well as his resource in alleviating the tedium of their unoccupied time, by setting them to work to cultivate a barren island, and converting it into a fruitful garden, whose produce was an extremely welcome adjunct to the invariable salt junk and biscuit of those days. Promotions, however, came, and he was made, at short intervals, successively Vice-Admiral of the White and of the Red.
But the year 1758 proved more eventful for our hero; and is perhaps the most memorable in his annals, for it witnessed his gallant attack and capture of Louisbourg—'once mistress of the seas,' and 'the key to French America,' but now consisting of a few fishermen's huts and some moss-covered ruins. This event directly led to the conquest of Canada.