General Pope was obliged to retreat as far as the Rappahannock, where his army took a position beyond the north fork of the river. The enemy continued to advance, and on the morning of the 20th, drove in the Union pickets and made an effort to cross the river at Kelly’s Ford. It was of the greatest importance to General Pope to retain communication with Fredericksburg, for by that way he was eagerly looking for reinforcements; and, therefore, his army bravely resisted the efforts of the rebels to cross the river, keeping up the resistance for two days. But the rebels slowly began to gain their object; and ascending the river, endeavored to turn the right of the Union army under General Sigel. At Sulphur Springs, they effected a crossing. The position of the Union army at this time was very perilous. General Sigel had orders to resist the rebels at every point below Sulphur Springs, and was at the same time expected to extend his line toward Warrenton. General Lee sent a large detachment of his men up the river, keeping the great ranks of the rebel army in front of General Pope’s line. There remained one of three things for General Pope to do; to retire by Fredericksburg, and thus lose direct communication with Washington; to abandon the line of the Rappahannock, by falling back on Warrenton; or to bring his whole force to bear upon the rebel flank and rear, then marching up the river. He chose to fight. The attack was made on the 23rd, in the morning, after a heavy rain, which had raised the Rappahannock several feet, carrying away the bridges, and rendering the fords impassable. General Sigel was ordered to attack the rebels at Sulphur Springs; and he did so, driving them back over the river. They destroyed the bridges behind them. He then moved down to Waterloo Bridge, whence General Pope’s line extended to Warrenton. Further advances of the enemy were perceived on the afternoon of this day. A large force of infantry, cavalry, and artillery, belonging to Stonewall Jackson’s command, were seen in the valley between Blue Ridge and Bull Run mountains, steadily marching toward Rectortown. General Pope now abandoned his line of communication with Fredericksburg, and made no attempt to oppose the rebels crossing at the Rappahannock Station. General Pope, however, deserves great praise for having, during eight days, resisted this advance of an overwhelmingly large army, But finding it impossible to withstand it on that line any longer, he chose a new position, well adapted for defence, extending his army from Warrenton to Gainesville. Reinforcements for General Pope’s army had by this time arrived, so that his numbers were increased to fifty-five thousand. But the rebel army numbered one hundred thousand. Day after day, for about a week, raids, skirmishes, battles, surprises, marches and counter-marches rapidly followed each other; and the rebels succeeded in seizing Manassas Junction, where they captured a large amount of stores.