_July 6._--This morning, at an early hour, Kilpatrick's crowd of prisoners were turned over into the hands of General French, and then his command marched to Hagerstown, taking possession of the place in advance of Stuart, whose approach about eleven o'clock was met with determined resistance, and, at first, with great success. A heavy battle was fought, in which Kilpatrick's men showed their usual prowess and strength. Had not Rebel infantry come to the aid of his cavalry, Stuart would have suffered a stunning blow. For several hours the contest was wholly between cavalry and light artillery. Charges of great daring and skill were made. One reporter says: "Elder gave them grape and canister, and the Fifth New York sabres, while the First Vermont used their carbines." In one of those charges, made in the face of a very superior force, Captain James A. Penfield, of the Fifth New York, at the head of his company, had his horse killed under him, and, while struggling to extricate himself from the animal, which lay upon him in part, he was struck a fearful blow of a sabre on the head, which came near severing it in twain. Thus wounded, with blood streaming down upon his long beard and clothes, he was made a prisoner. In a similar charge the gallant Captain Ulric Dahlgren lost a leg, though not his valuable life. It appeared as though the Rebels were afforded an opportunity to avenge themselves in part for the shameful losses which they had sustained in this very place by the strategic operations of a Union scout, by the name of C. A. Phelps, during the incipient step of the invasion. We will let the scout relate his own story, which is corroborated by a signal-officer, who, from one of the lofty peaks of the mountains, witnessed the exciting denouement. The scout proceeds to say: "I was very anxious to learn all about General Stuart's force and contemplated movements, and resolved to see the general himself or some of his staff-officers, soon after he entered Hagerstown. "Accordingly I procured of a Union man a suit of raglings, knocked off one boot-heel to make one leg appear shorter than the other, and put a gimblet, a tow-string, and an old broken jack-knife in my pockets. My jewelry corresponded with my clothes. I adopted the name of George Fry, a harvest-hand of Dr. Farney, from Wolfetown, on the north side of the mountain, and I was a cripple from rheumatism. Having completed arrangements with Dr. Farney, Mr. Landers, and other Union men, that they might be of service to me in case the Rebels should be suspicious of my character, I hobbled away on my perilous journey, and entered the city by leaping the high stone wall which guards it on the north side near the depot. This occurred just as the town-clock struck one.