On Saturday the 26th August (two days prior to the National Democratic Convention), immense numbers of persons came flocking to Chicago, indeed at no former time in the history of the city was there such an influx of strangers; they came in the cars and in wagon trains, and on horseback. One county alone sent nearly a thousand men. It was a noticeable fact that almost all persons who came into the city were well armed, and some of them even brought muskets. Treason was now rampant, and it would not be difficult, in looking around upon the most unprepossessing groups, and to hear the language, to fancy one's-self in Charleston, or some other nest of treason. From all the men who came to the city we did not, in a single instance, hear one good, hearty expression of Unionism, but our "Southern brethren and their rights," and this "wicked war," &c., &c., were the topics of conversation, and it was safe to set it down, that this was the Peace wing of that most remarkable bird,--Democracy of 1864. The writer was in close communication with Col. Sweet, commandant at Camp Douglas, and by aid of our auxiliaries not an item of information concerning the hostile intentions of the party transpired, that was not known instantly by Col. Sweet,--special carriers or orderlies conveying our dispatches. It must not be supposed that our observations were confined to Chicago. Our channels of communication with the principal points in the West were unobstructed; our "telegraphic cable" was in fine working order, and if those wise heads for a moment fancied that Col. B.J. Sweet might be caught napping, they were the worst self-deceived men we have ever seen. Col. Sweet proceeded with all caution and celerity to make his arrangements, and we beg the Colonel not to regard it as a breach of confidence in us to say, that the guns were in such a position and so well managed, that had there been any attempt to have assaulted the camp, there would not have been able-bodied traitors enough left, to have carried the killed and wounded to secure retreats. Almost any officer, perhaps, less cool than Col. Sweet would have blustered about in such a manner as to have rendered himself not only positively offensive to the citizens, but would have placed the city under martial law, and doubtless precipitated the very event it was wise for a time to avert. Col. Sweet was cool, and managed the matter with the most perfect military ability and skill. He compelled everybody, friend and foe, to respect him by his dignified, gentlemanly bearing, and yet there was that about his appearance that told plainer than words, that while he was courteous, polite, kind and willing to do all in his power and consistent with his duty to preserve the peace, yet had an outbreak been begun, of all men in Chicago, rebels and sympathisers would prefer to get as far as possible from Col. Sweet, or the reach of his influence. This gallant officer had his men under