The last of the fortified boundary, or chain of redoubts, was carried by storm on the 10th September; the French were driven in, and Coote had forty killed and seventy wounded; Major Monsoon had one of his legs torn off by a cannon-shot.
A body of Scottish Highlanders, who had just been landed from the Sandwich East Indiaman, behaved with their accustomed valour in this affair. Passing Draper's grenadiers in their eagerness to get at the enemy, they threw down their muskets, and with their bonnets in one hand, and their claymores in the other, hewed a passage through a jungle hedge, fell with a wild cheer upon the soldiers of Lally, and cut a whole company to pieces. Only five Highlanders and two grenadiers were shot. The Highlanders were fifty in number, and were commanded by a Captain Morrison. They belonged to the 89th Highland Regiment, which had been raised among the Gordon clan in the preceding year.
After that night, the operations of Lally were confined to the walls of Pondicherry.
Of the guns taken by the Highlanders, seven were found to be 18-pounders, loaded to the muzzle with square bars of iron six inches long, jagged pieces of metal, stones and bottles. They were on Lally's strongest battery, which was formed before a thick wood, one mile in front of Pondicherry, which could no longer have any succour from the seaward, as the Chef d'Escadre had sailed for Brest, where he arrived in April, 1761. Thus a 54-gun ship, a 36-gun frigate, and four Indiamen were left behind, and hopelessly shut up in the roadstead.
In the month of October, Admiral Stevens, who had relieved Admiral Cornish, sailed with his portion of the fleet for Trincomalee to refit, leaving five sail of the line, under Captain Haldane, to blockade Pondicherry, while Colonel Coote pressed on the investment by land. By their dispositions and vigilance, the dense population became distressed for provisions even before a siege was formally begun, and while the incessant rains rendered a closer conflict impracticable. The blockade was supported by a number of batteries judiciously posted; by these the garrison was harassed on one hand, while their supplies were cut off on the other; and these posts were gradually pushed nearer and nearer to the town, notwithstanding the deluge of rain, which had swollen the broad currents of the Chonenbar and the Gingi, two rivers that unite near it, and roll their tides together to the sea.
On the 26th November, the rains abated, and Colonel Coote directed his engineers to erect batteries in other places; from whence, without being exposed, they could enfilade the works of the garrison, which was strictly closed in, and by the failure of the Mysorean rajah to fulfil his promise, was now enduring the utmost privations from scarcity of food. Lally was compelled to turn out of the town a vast multitude of native women and children; but Coote drove them back again, and, as the batteries were firing at the time, a great number of these poor wretches were slain or severely wounded.
During these operations, Captain Sir Charles Chalmers of Cults, a gallant Scottish baronet who served in Coote's artillery, died of fatigue. He possessed only the honours of his family, their estates having been forfeited for adherence to the house of Stuart about fifteen years before.
On the night of the 7th October, the armed boats of the British fleet were pulled with muffled oars into the harbour, and two ships were cut out, under the very muzzles of Lally's cannon; but not before he had killed and wounded thirty officers and men. The prizes were the Balcine and Hermione, a frigate and a valuable Indiaman. In this affair Lieutenant Owen, of H.B.M. ship Sunderland, lost an arm.
To encourage the British, the Nabob of Arcot promised to divide among them fifty lacs of rupees on the day Pondicherry should surrender, and, as each lac was valued at 12,600l. sterling, the greatest enthusiasm prevailed among the officers, soldiers, and seamen: moreover, as all the French colonists who fled from other places had stored up their effects in Pondicherry, the treasure there was reputed to be enormous.