An alert enemy, under such circumstances, would have insisted upon interfering, morning, noon and night, with the exercises of the adversary's military kindergarten. A commander on the Confederate side, possessed of large capacity and energy, would have interrupted the work of McClellan by daily and disturbing incursions in force; or more probably still he would have crossed the Potomac, and forced McClellan to accept battle in Maryland or Pennsylvania with his utterly untrained and badly demoralized volunteers. All of this was so obvious that dulness itself must have seen it. Yet the two Confederate generals at Manassas and Centreville seem never to have opened their eyes to the opportunity, and so nothing in this way was done. In the meanwhile, McClellan was diligently strengthening himself. He was daily adding to his forces those new levies of volunteers which came freely from the North in spite of the disaster at Manassas. He was also strengthening the fortifications at Washington in a way that made their conquest forever afterwards a hopeless enterprise. He sent out many columns to one point and another, not to bring on battle, but to practice his men in the school of the soldier, and to use them to "standing fire" without flinching. Incidentally, these operations brought on only one action of considerable moment, that which occurred at Leesburg or Ball's Bluff on the Potomac, on the twenty-first of October. It was an action involving rather heavy losses particularly to the Federal troops, but it had no strategic significance whatever. Military critics have not been able to conjecture why the action was brought on at all. Under orders of General C. P. Stone, Colonel Baker crossed the Potomac near Leesburg to reconnoiter at a point where no reconnoissance was needed, and where no action could by any possibility have aught of significance or consequence. Colonel Baker was disastrously defeated and killed. The Union troops were driven into the river, and large numbers of them were drowned. The effect of the action was to increase rather than diminish the demoralization that the Manassas battle had wrought in the Union army, and to increase in like proportion the self-confidence of the Confederates--all but their generals. Even after this second victory they did not push their columns across the Potomac.