The greatest secrecy was observed in this enterprise. Not more than twenty or thirty of the prisoners knew of the tunnel's existence, and they were by a solemn oath bound not to reveal their knowledge. One would suppose that there could have been no danger from the prisoners themselves; but subsequent events proved that these precautions were only too necessary.
This tunnel was started in one of the sheds, under a bank, about twenty feet from the Dead Line, and it had progressed about ten feet when I first transformed myself into a woodchuck.
Our mining tools consisted of a strap hinge, fastened to a stick about two feet long, a tin dipper, and some sacks. The manner of digging was to lie upon the side, and with the hinge work out the hard clay. This was loaded into the sacks by means of the cup. A confederate, holding a cord attached to the sack, would draw it back and empty it, and then crawl back to the digger, who by this time would have another sack of dirt ready.
After getting about thirty feet from the mouth of the tunnel, the air became so bad that a candle would not burn for a second, and the number of diggers who could endure this atmosphere was reduced to two or three. The sensation on first getting back to the mouth end of the tunnel, was that of suffocation; the perspiration would start from every pore; but after a few moments this would partially pass away. It was, however, nothing unusual for the digger, after his work in the tunnel, to faint away upon getting to fresh air.
The natural inquiry will arise: What became of the dirt? The negroes took care of it for us. Every morning the ground in the pen was nicely swept up, and the dirt hauled away by negroes. We piled up the dirt taken from the tunnel, and when the negroes came with their cart, they would take great pains to put the red dirt on the bottom of the cart, and cover it with the black. They knew what we were doing, by the appearance of this fresh earth; but when they came to one of our red piles, it was only by a wink of the eye or a broad grin that they indicated their knowledge.
We had progressed about ninety feet with our tunnel, and were outside the guards. We only needed to make thirty feet more to come out behind a brick wall across the street.
Betrayed
We had then been working on it for about a month but at this juncture we were betrayed by one of our own men, a Lieutenant of a cavalry regiment, by the name of Silver.
The first intimation we had of our betrayal, was one morning at roll call. I think it was on the first day of July, after we had been driven to one end of the pen, after the custom I have described. We saw the Confederate officer and a guard inspecting the ground in the vicinity of the tunnel. This they did by stabbing a bayonet into the ground, as no one could detect the existence of the tunnel by the eye, the mouth being covered and dirt swept over it, so as to make it resemble the surface.