But, while he was thus foolishly wearing out the telegraph lines between his headquarters and Washington, Lee was putting into operation a plan which would have been rash to the point of folly against a really able soldier but which was perfectly justified against an incompetent. This plan was to divide his army, which numbered less than 50,000 men, into two parts, sending "Stonewall" Jackson with 25,000 to get behind the Union forces, while he attracted their commander's attention at the front. Of course, if Pope had discovered this audacious move, he could easily have crushed the divided Confederate forces in turn before either could have come to the other's rescue, for he had 70,000 at his command. But the armies were not far from Manassas or Bull Run, where the first important engagement of the war had been fought and Lee know every inch of the ground. Moreover, he believed that all Pope's provisions and supplies upon which he depended for feeding his army were behind him, and that, if Jackson succeeded in seizing them and getting between the Union army and Washington, Pope would lose his head and dash to the rescue regardless of consequences. Great, therefore, as the risk was he determined to take it, and Jackson circled away with his 25,000 men, leaving Lee with the same number confronting an army of 70,000 which might have swept the field. But its commander never dreamed of the opportunity which lay before him and he remained utterly unsuspicious until the night of August 26, 1862, when his flow of telegrams was suddenly checked and he was informed that there was something the matter with the wires connecting him to Washington. There was, indeed, something the matter with them, for Jackson's men had cut them down and were at that moment greedily devouring Pope's provisions, helping themselves to new uniforms and shoes and leaving facetious letters complaining of the quality of the supplies. For a while, however, the Union general had no suspicion of what was happening, for he interpreted the interference with the telegraph wires as the work of cavalry riders whom a comparatively small force could quickly disperse. But when the troops dispatched for this purpose came hurrying back with the news that Jackson's whole army was behind them, he acted precisely as Lee had expected, and completely forgetting to close the doors behind him, dashed madly after "Stonewall," whom he regarded as safe as a cat in a bag. The door which he should have closed was Thoroughfare Gap, for that was the only opening through which Lee could have led his men with any hope of arriving in time to help his friends, and a few troops could have blocked it with the utmost ease. But it was left unguarded and Pope had scarcely turned his back to spring on Jackson before Lee slid through the Gap and sprang on him.