One of our scouts reached Hnaert. town ast night baviug luft Middletuwn 18 miles soutli-pnst of tliut placa, at 5 o'clock, P. M. He report tiiat tlio rebels were at Hagerstown in considerable forcé, and advancing. All tho rolling atock of the railroud had beeo remorad from Hagorstown, and tlio tolegiaph office h;s been openud at Greoncastlo trom which place our soouta and raessco' gers will bu sent. Pmr.ADEi.i'iiiA, Sopt. 9. The special correspondent of the Prut of thU city, returning from Sykesvillo Md , says that bu has jast left Monrovi Mi] , on account of tha approach of tira rebels, and a party of their cavalry oij. tered that place on Sunday. Many speculations ure rife relativo to the inovementa, intents and purposes of Stonewall Jickson. Somo say that bo is ou Iris way with a Iarge anny to Qettysburg, Pa., so is to be witbiu striking distance of Ohambersburg or York, and that he is already near Ilanover, whila otliers assert that he had marched to Westminster, and will move on Bulti. inore in that direction. Othera asaert that this is ouly a feint to cover hU eatrance iuto Pennsylvania.