About three weeks ago General McDowell took upon himself the responsibility to attack the enemy concentrated at Manassas. Deciding upon this step, McDowell showed the determination of a true soldier, and a cool, intelligent courage. According to rumors permeating the whole North; rumors originated by secessionists in and around Washington, and in various parts of the free States; rumors gulped by a part of the press, and never contradicted, but rather nursed, at headquarters, Manassas was a terrible, unknown, mysterious something; a bugbear, between a fortress made by art and a natural fastness, whose approaches were defended for miles by numberless masked batteries, and which was filled by countless thousands of the most ferocious warriors. Such was Manassas in public opinion when McDowell undertook to attack this formidable American Torres Vedras, and this with the scanty and almost unorganized means in men and artillery allotted to him by the senile wisdom of General Scott. General McDowell obtained the promise that Beauregard alone was to be before him. To fulfil this promise, General Scott was to order Patterson to keep Johnston, and a movement was to be made on the James River, so as to prevent troops coming from Richmond to Manassas. As it was already said, Patterson, a special favorite of General Scott, kindly allowed Johnston to save Beauregard, and Jeff. Davis with troops from Richmond likewise was on the spot. McDowell planned his plan very skilfully; no European general would have done better, and I am sure that such will be the verdict hereafter. Some second-rate mistakes in the execution did not virtually endanger its success; but, to say the truth, McDowell and his army were defeated by the imbecility of the supreme military authority. Imbecility stabbed them in the back.

One part of the press, stultified and stupefied, staggered under the blow; the other part showed its utter degradation by fawning on Scott and attacking the Congress, or its best part. The Evening Post staggered not; its editors are genuine, laborious students, and, above all, students of history. The editors of the other papers are politicians; some of them are little, others are big villains. All, intellectually, belong to the class called in America more or less well-read men; information acquired by reading, but which in itself is not much.

The brothers Blair, almost alone, receded not, and put the defeat where it belonged—at the feet of General Scott.

The rudis indigestaque moles, torn away from Scott's hands, already begins to acquire the shape of an army. Thanks to the youth, the vigor, and the activity of McClellan.

General Scott throws the whole disaster on politicians, and abuses them. How ungrateful. His too lofty pedestal is almost exclusively the work of politicians. I heard very, very few military men in America consider Scott a man of transcendent military capacity. Years ago, during the Crimean campaign, I spent some time at West Point in the society of Cols. Robert Lee, Walker, Hardee, then in the service of the United States, and now traitors; not one of them classed Scott much higher above what would be called a respectable capacity; and of which, as they said, there are many, many in every European army.

If one analyzes the Mexican campaign, it will be found that General Scott had, comparatively, more officers than soldiers; the officers young men, full of vigor, and in the first gush of youth, who therefore mightily facilitated the task of the commander. Their names resound to-day in both the camps.

Further, generals from the campaign in Mexico assert that three of the won battles were fought against orders, which signifies that in Mexico youth had the best of cautious senility. It was according to the law of nature, and for it it was crowned with success.

Mr. Seward has a very active intellect, an excellent man for current business, easy and clear-headed for solving any second-rate complications; but as for his initiative, that is another question. Hitherto his initiative does not tell, but rather confuses. Then he sustains Scott, some say, for future political capital. If so it is bad; worse still if Mr. Seward sustains Scott on the ground of high military fitness, as it is impossible to admit that Mr. Seward knows anything about military affairs, or that he ever studied the description of any battle. At least, I so judge from his conversation.

Mr. Lincoln has already the fumes of greatness, and looks down on the press, reads no paper, that dirty traitor the New York Herald excepted. So, at least, it is generally stated.

The enemies of Seward maintain that he, Seward, drilled Lincoln into it, to make himself more necessary.