On July 8 Prideaux summoned the fort to surrender, and, his summons being rejected, began to invest the place. No great skill was shown in the investment, and on July 20 the English general was accidentally killed by the bursting of a shell from one of his own guns. The command devolved on Johnson, who heard that a relief {295} force was coming down Lake Erie--a force which numbered at least 1,200 men all told, and was led by some of the best border fighters in Canada, including Ligneris, who had in the preceding year been in charge of Fort Duquesne. Johnson marched out to intercept them on the road between the fort and the falls, attacked them at once in front and on the flank, and gained a complete victory. The French officers were taken prisoners, their troops were utterly routed and broken up, and the survivors retreated westward to Detroit, abandoning Lake Erie and the whole of the Ohio country. It was on July 24 that the fight took place, and on the following day Pouchot, having verified the news of the French defeat, surrendered Niagara. One of the terms of the surrender was that the prisoners should be protected from the Indians by an English escort, the massacre at Fort William Henry being evidently borne in mind; and on this condition six hundred Frenchmen were sent to New York. [Sidenote: _Result of its fall._] Thus, for the second time, Sir William Johnson had rendered signal service to the English cause; and with the fall of Niagara the French lost all command of the lower lakes. Their only communication now with Detroit and the far West was by the old route of the Ottawa river, and their scheme of conquest in the lands of the Ohio was wholly and for ever undone. 'The taking of Niagara broke off effectually that communication, so much talked of and so much dreaded, between Canada and Louisiana; and by this stroke one of the capital political designs of the French, which gave occasion to the present war, was defeated in its direct and immediate object.'[8] On hearing of the success, Amherst sent up General Gage to replace Prideaux, with orders to come down the St. Lawrence and join in the combination against central Canada; but the force was small, Gage, like Amherst, was cautious, and the summer passed {296} away without any further success by the troops on Lake Ontario. [Footnote 8: _Annual Register_ for 1759, p. 34.] [Sidenote: _Amherst's advance._] [Sidenote: _The French abandon Ticonderoga and Crown Point._]