On the 3d of July Gen. Nathaniel Lyon, at the head of about 2,000 troops, left Boonville for the Southwest to co-operate with Sigel. On the 25th of June five companies of cavalry, six companies of regular infantry and dragoons, and ten companies of Kansas volunteers, in all about 1,600 men, under command of Maj. S. D. Sturgis, left Kansas City, destined also for Southwest Missouri. At Grand River, in Henry county, the two commands formed a junction, and then started for Sigel. Hearing of the latter’s defeat, and retreat to the eastward, Gen. Lyon changed his direction more to the eastward and came into this county about the 13th of July, going into camp near Pond Spring, on section 31, township 29, range 23, in the western part of the county. Lyon came into the town of Springfield July 13th, leaving, as he wrote to Chester Harding, his troops, “a few miles back.” Gen. Lyon was mounted on an iron-gray horse, and had an escort or body-guard of ten men of the 1st regiment U. S. regular cavalry, all of whom were men remarkable for their large size, strong physique, and fine horsemanship. Lyon treated the citizens with courtesy and kindness, although impressing their provisions and animals, to some extent, for the use of his men. As soon as he arrived in this quarter he communicated with Sigel, and with Gen. Fremont at St. Louis, asking the latter to send him reinforcements at once. He also busied himself in recruiting for the Federal service—issuing commissions to officers of Home Guard companies, and mustering in enlisted men. Ho was visited by Union men from counties north and east 75 miles away. SWEENEY’S EXPEDITION TO FORSYTH. Saturday, July 20, about 1,200 men were detailed under Gen. Sweeney to break up a secession camp reported to be at Forsyth, the county seat of Taney county. The command was composed of the two companies of regular cavalry, under Capt. D. S. Stanley; a section of Capt. Totten’s battery, in charge of Lt. Sokalski; about 500 men of the 1st Iowa Infantry, under Lt. Col. Merritt; Capt. Wood’s company of mounted Kansas volunteers, and the 2d Kansas Infantry, under Col. Mitchell. The expedition reached Forsyth in the afternoon of Monday, captured the town with but little difficulty, driving out about 200 State Guards, who had been quartered in the court-house, and secured some blankets, clothing, guns, provisions, horses and one or two prisoners. A quantity of lead was taken from a well into which it had been thrown. Three shells were thrown into the court-house after the Federals had possession of the town.