FORE:Frederick, being constrained by the approach of General Daun to raise the siege of Dresden, retired to his intrenched camp at Schlettau. Leaving fifteen thousand men to guard the camp, he, on the 1st of August, before the dawn, crossed the Elbe, and was again on the rapid march toward Silesia. His army consisted of thirty thousand men, and was accompanied by two thousand heavy baggage-wagons. In five days the king marched over one hundred miles, crossing five rivers. Armies of the allies, amounting504 to one hundred and seventy-five thousand Austrians and Russians, were around him��some in front, some in his rear, some on his flanks.150At length Frederick, weary of these unavailing efforts, dashed off in rapid march toward the River Neisse, and with his vanguard, on the 11th of September, crossed the river at the little town of Woitz, a few miles above the city. The river was speedily spanned with his pontoon bridges. As the whole army hurried forward to effect the passage, Frederick, to his surprise, found the Austrian army directly before him, occupying a position from which it could not be forced, and where it could not be turned. For two days Frederick very earnestly surveyed the region, and then, recrossing the river and gathering in his pontoons, passed rapidly down the stream on the left or northern bank, and, after a brief encampment of a few days, crossed the river fifteen miles below the city. He then threw his army into the rear of Neipperg��s, so as to cut off his communications and his daily convoys of food. He thus got possession again of Oppeln, of the strong castle of Friedland, and of the country generally between the Oder and the Neisse rivers.