In our previous discussion of the progress of the war upon Lake Ontario, we left Commodore Chauncey in winter quarter at Sackett's Harbor, building new ships, and making vigorous efforts to secure sailors to man them. His energy met with its reward; for, when the melting ice left the lake open for navigation in the spring of 1813, the American fleet was ready for active service, while the best vessels belonging to the British were still in the hands of the carpenters and riggers. The first service performed by the American fleet was aiding Gen. Pike in his attack upon York, where the Americans burned an almost completed twenty-four-gun ship, and captured the ten-gun brig "Gloucester." The land forces who took part in this action were terribly injured by the explosion of the powder-magazine, to which the British had applied a slow-match when they found they could no longer hold their position. This battle was fought April 27, 1813. One month later, the naval forces co-operated with the soldiery in driving the British from Fort George, on the Canada side of the Niagara River, near Lake Ontario. Perry came from Lake Erie to take part in this action, and led a landing party under the fire of the British artillery with that dashing courage which he showed later at the battle of Put-in-Bay. The work of the sailors in this action was cool and effective. Their fire covered the advance of the troops, and silenced more than one of the enemy's guns. "The American ships," writes a British historian, "with their heavy discharges of round and grape, too well succeeded in thinning the British ranks." But by this time the British fleet was ready for sea, and left Kingston on the 27th of May; while Chauncey was still at the extreme western end of the lake. The enemy determined to make an immediate assault upon Sackett's Harbor, and there destroy the corvette "Gen. Pike," which, if completed, would give Chauncey supremacy upon the lake. Accordingly the fleet under Sir James Lucas Yeo, with a large body of troops under Sir George Prescott, appeared before the harbor on the 29th. Although the forces which rallied to the defence of the village were chiefly raw militia, the British attack was conducted with so little spirit that the defenders won the day; and the enemy retreated, leaving most of his wounded to fall into the hands of the Americans. Yeo then returned to Kingston; and the American fleet came up the lake, and put into Sackett's Harbor, there to remain until the completion of the "Pike" should give Chauncey control of the lake. While the Americans thus remained in port, the British squadron made brief incursions into the lake, capturing a few schooners and breaking up one or two encampments of the land forces of the United States.