But such paltry success could avail the French little, for Bradstreet's capture of Fort Frontenac had already decided the fate of Fort Duquêsne. The French commander, his supplies being cut off, was obliged to dismiss the greater number of his men; otherwise Forbes could hardly have penetrated to the Ohio in that year. The elements fought for the French. Heavy rain ruined Bouquet's new road; the horses being underfed and overworked kept breaking down fast; the magazines at Raystown and Loyalhannon were emptied faster than they could be replenished; and Forbes was in despair. All through October the rain continued until at length it gave place to snow, and the roads became a sea of mud over which retreat and advance were alike impossible. At the beginning of November the General, though now sick unto death, was carried to Loyalhannon, where he decided that no attack could be attempted for that season. Intelligence, however, was brought that the French were so weak in numbers as to be defenceless; and on the 18th, twenty-five hundred picked men marched off without tents or baggage, Forbes himself travelling in a litter at their head. At midnight of the 24th the sentries heard the sound of a distant explosion, and on the next day at dusk the troops reached the blackened ruins of what had been Fort Duquêsne. The fortifications had been blown up; barracks and store-houses were in ashes; there was no sign of anything human except the heads of the Highlanders who had been killed in Grant's engagement, stuck up on poles with their kilts hung in derision round them. Their Highland comrades went mad with rage at the sight; but the French and their allies were gone, having evacuated and destroyed the fort and retired to the fort of Venango farther up the Alleghany river. Forbes planted a stockade around a cluster of huts that were still undestroyed, and named it Pittsburg in honour of the minister. Arrangements were then made for leaving a garrison of two hundred Provincials to hold the post, for there could be no doubt that the French would collect a force from Venango and Niagara to endeavour to retake it. The garrison indeed was far too small, but there was not food enough for more; so this handful of poor men was left perforce to make the best of its solitude during the dreary days of the winter.

One duty still remained to be done before Forbes's column turned homeward,—to search for the bones of those who had fallen with Braddock. A party of Pennsylvanians made their way through the forest to the Monongahela, Major Halket of Forbes's staff accompanying them. Among the multitude of ghastly relics two skeletons were found lying together under one tree. Halket recognised the one by a peculiarity of the teeth as that of his father, Sir Peter Halket of the Forty-fourth; and in the other he thought that he saw his brother, who had fallen by his side. The two were wrapped in a Highlander's plaid and buried in one grave, under a volley fired by the Pennsylvanians. The rest of the remains were buried together in one deep trench; and then at the beginning of December the troops marched back to Pennsylvania with the dying Forbes in their midst. With great difficulty the General was brought still living to Philadelphia, where he lingered on through the winter and died in the following March. Though no brilliant action marked his advance to the Ohio he had accomplished his work against endless difficulties and in extremity of bodily torture; and that work was the taking from France of half of her Indian allies, the relief of the western border from Pennsylvania to Maryland from Indian raids, and the opening to the British of the vast regions of the West.

So ended the American campaign of 1758. The French had been struck hard on both flanks, at Louisburg in the north and on the Ohio in the south, but in the centre they had held their own. Two parts out of three of Pitt's design had been accomplished; but the most important success of all was that achieved by Bradstreet in severing the French communications at Fort Frontenac. It may be that Pitt thought best to adhere to the plan of operations mapped out for him by Loudoun, or it may be that he wished to retrieve the reputation lost by Braddock's defeat; but the fact remains that he meditated no attack on Niagara or Fort Frontenac, the capture of either of which would have entailed that of Fort Duquêsne, and that despite the industry of Bouquet and the tenacity of Forbes the advance to the Ohio would have been impossible but for the brilliant and successful enterprise of Bradstreet.