A dreadful steamboat catastrophe occurred on Lake Erie on the 19th of August. The steam-propeller Ogdensburgh ran into the steamer Atlantic, striking her just forward of the wheel-house, and injuring her so seriously that, after going a mile or two toward the shore, she sunk. The propeller, not understanding the full damage of the collision, and anxious for her own safety, did not go to the rescue of her passengers until half an hour after the accident. More than a hundred persons lost their lives, the greater portion of them being Norwegian emigrants huddled together on the forward deck, and unable, through their ignorance of English, to avail themselves of the means of safety suggested. Very conflicting statements in regard to the cause of the collision have been published;--the night was not very dark, both vessels had signal lights and a watch on deck. The matter is undergoing judicial investigation.----On the Hudson River still another accident occurred on the 4th of September. As the steamer _Reindeer_ lay at the wharf at Bristol landing, about forty miles below Albany, one of her connection pipes burst, and _twenty-seven_ persons, mainly those in the after-cabin, were killed--fifty more being considerably injured.----A National Convention of the Free-Soil party was held at Pittsburgh on the 11th of August, at which John P. Hale, of New Hampshire, was nominated for President, and George W. Julian, of Indiana, for Vice-President, as the candidates of that party.----A meeting of delegates is to be held at Macon, Georgia, on the 20th of October, for the purpose of calling an Agricultural Congress of the Slaveholding States--the chief objects of which are declared to be to develope the resources, combine the energies, and promote the prosperity of the Southern States, and to cultivate the aptitudes of the negro race for civilization; so that when slavery shall have fulfilled its mission, a system may be authorized which shall relieve the race from its servitude, without sinking it to the condition of the free negroes at the North and in the West Indies.