A few words will tell what was to be done, and how it was accomplished.  The tunnel began near the floor of the cellar, eight or nine feet underground.  Its length would need to be seventy or eighty feet.  Only one man could work in it at a time, and this he had to do while crawling forward with his face downward, and with such tools as pocket-knives, small hatchets, sharp pieces of wood, and a broken fire-shovel.  After the opening had made some progress two men could work in it, one digging, the other carrying back the earth, for which work frying-pans were brought into use.

Another point of some little importance was the disposal of the dirt.  This was carelessly scattered over the cellar floor, with straw thrown over it, and some of it placed in boxes and barrels.  The whole amount was not great, and not likely to be noticed if the officials should happen to enter the cellar, which had not been cleaned for years.

The work here described was begun in the latter part of January, 1864.  So diligently was it prosecuted that the tunnel was pronounced finished on the night of February 8.  During this period only two or three men could work at once.  It was, indeed, frightfully exhausting labor, the confinement of the narrow passage and the difficulty of breathing in its foul air being not the least of the hardships to be endured.  Work was prosecuted during part of the period night and day, the absence of a man from roll-call being concealed in various ways, as already mentioned.

The secret had been kept well, but not too well.  Some workers had divulged it to their friends.  Others of the prisoners had discovered that something was going on, and had been let into the affair on a pledge of secrecy.  By the time the tunnel was completed its existence was known to something more than one hundred out of the eleven hundred prisoners.  These were all placed on their word of honor to give no hint of the enterprise.

The night of February 8 was signalized by the opening of the outward end of the tunnel.  A passage was dug upwards, and an opening made sufficiently large to permit the worker to take a look outward into the midnight air.  What he saw gave him a frightful shock.  The distance had been miscalculated; the opening was on the wrong side of the fence; there in full sight was one of the sentinels, pacing his beat with loaded musket.

Here was a situation that needed nerve and alertness.  The protruded head was quickly withdrawn, and the earth which had been removed rapidly replaced, it being packed as tightly as possible from below to prevent its falling in.  Word of the perilous error was sent back, and as the whisper passed from ear to ear every heart throbbed with a nervous shock.  They had barely escaped losing the benefit of their weeks of exhausting labor.

The opening had been at the outward edge of the fence.  The tunnel was now run two feet farther, and an opening again made.  It was now on the inside of the fence, and in a safe place, for the stable adjoining the yard was disused.