While Porter was slowly approaching our coast, on his return from the Pacific, events on our northern frontier were assuming an entirely different aspect from that which they had worn for the last two years. In the spring, just before and after Congress adjourned, small expeditions on both sides were set on foot; one, on our part, to Mackinaw, to aid in carrying out Armstrong's plan for the summer campaign. This, like all the previous plans looked to the same result, the details being varied apparently for the sole purpose of appeasing the people, who it was thought, would not allow a repetition of those manoeuvres which had ended in such signal disgrace. It was therefore proposed, first to humble the Indians in the north-west, by capturing Mackinaw, and thus hold the key of that whole region, so valuable for its fur trade, and then march an army from the east of Lake Erie to Burlington Heights, and seize and fortify that position till the co-operation of the Ontario fleet and the troops at Sackett's harbor could be secured, when a rapid advance might be made on Kingston, and after its reduction, on Montreal. The Secretary clung to the conquest of Canada with a tenacity that deserved success, but this plan also utterly failed, and the progress of the campaign brought about results widely different from those anticipated. That part of it looking to the seizure of Mackinaw, was placed under the direction of Colonel Croghan and Major Holmes, with whom Captain Sinclair, recently appointed to the command of the upper lakes, was to co-operate with a portion of his fleet--the other portion to aid in the expedition against Burlington Heights. Major Holmes had at first been appointed by the Secretary to command the land forces, but Colonel Croghan, stationed at Detroit, and senior officer during Colonel Butler's absence, denied the right thus directly to appoint him, insisting that the commission should go through his hands. A correspondence followed, which delayed the expedition till the third of July. In the mean time, a British force, under Colonel McDowell, had visited and reinforced all the posts on the northern lakes, penetrating even beyond Mackinaw. While Holmes and Sinclair were detained till Colonel Croghan and the Secretary could settle a question of etiquette, the English, who had again acquired the ascendancy on Lake Ontario, by building more ships, made an attack on Sackett's Harbor. Being repulsed, Sir James Yeo then sailed for Oswego, to destroy materials for ship building, etc., which he supposed to be assembled there. He arrived on the 5th of May, and began to bombard the place. The American garrison at the fort, consisted of three hundred men under Colonel Mitchell, with five guns, three of which were almost useless. The place contained at that time, but five hundred inhabitants. The schooner Growler being in the river, and exposed to certain capture, was sunk, and her cannon transferred