Frequently "contrabands" feel their way through the enemy's pickets under cover of the night, and through the tangled brushwood which abounds, and reach our lines safely. From them we gain much valuable information of the state of things in "Dixie." Some of them, we learn, were employed by Rebel leaders in constructing forts and earthworks, and in various ways were made to contribute muscle to the Southern Confederacy. They have strange and exciting stories to tell us, and yet it seems as though they might be of great service to us, if we saw fit to employ them, as guides in our movements. Their heart is with us in this conflict. They hail us as friends, and entertain wild notions about a jubilee of liberty, for which they are ever praying and singing, and look upon us as their deliverers. How they have formed such opinions is somewhat difficult to conjecture, especially when we consider the anomalous treatment they have received from our hands. The authorities have seemed to be puzzled with regard to them; and there are cases where they have even been returned to their former owners. And yet there seems to be an instinctive prophecy in their natures, which leads them to look to Northmen for freedom. Their presence in our camps becomes a sort of inspiration to most of us, and we only wish that their prayers may be answered, and that every chain of servitude may be broken. This sentiment at times breaks out in such as the following poetic strain: "In the beauty of the lily Christ was born across the sea, With a glory in His bosom that transfigures you and me As He died to make men holy, let us die to make them free." And as slavery was the cause, and not, as some say, the pretext, of the war, if the Union arms succeed, this "irrepressible conflict" and villanous wrong must come to an end. Our confidence in the ultimate success of our arms is daily increasing. Since the first of August our ranks have been wonderfully swelled; and now regiment after regiment, battery after battery, is pouring in from the North, filling the camps of instruction, and manning the fortifications around Washington. Meanwhile, earthworks are being constructed on all the high hills and commanding positions; strong abatis are made of the forest-trees, and every thing done that can give the city an air of security, and the country round about the appearance of a bristling porcupine. Should this influx of troops continue, we shall be compelled to advance our lines for very room on which to station them. We have some intimations that our advance to this point to-day is preparatory to such a movement.