Some time after this Trenck meditated another and a far bolder plan of escape. The garrison of Magdeburg was but 900 strong, and there were at least 7000 Croat prisoners of war in the fortress. He proposed to gain access to the Croats by bribing his jailers, and then putting himself at their head to seize the place for Maria Theresa. He sent to Vienna for 2,000 ducats, but failed to obtain them, and the project came to nothing.
He then once more began his mining operations, and had already made considerable progress with them, when the governor of the fortress becoming mad, he was replaced by the hereditary Prince of Hesse Cassel, who treated Trenck with so much kindness that the grateful prisoner pledged himself not to attempt to escape. This state of things continued for eighteen months, at the end of which time the prince, leaving the fortress in consequence of the death of his father, Trenck considered himself justified in making another effort for liberty. He accordingly procured the necessary tools with the same facility as before, and was opening up one of his old galleries, when an accident happened that had nearly put an end to his project and his life.
“While mining under the foundation of the ramparts,” he says, “just as I was going to carry out the sand bag, I struck my foot against a stone in the wall, which fell down and closed up the passage. What was my horror to find myself thus buried alive! After a short time for reflection, I began to work the sand away from the side that I might obtain room to turn round. By good fortune there were some feet of empty space into which I threw the sand as I worked it away, but the small quantity of air soon made it so foul that I a thousand times wished myself dead, and made several attempts to strangle myself. Further labour began to seem impossible. Thirst almost deprived me of my senses, but as often as I put my mouth to the sand I inhaled fresh air. My sufferings were incredible, and I imagine I passed full eight hours in this distraction of horror. Of all dreaded deaths surely such a one as this is the most dreadful. My spirits fainted, again I somewhat recovered, again I began to labour, but the earth was as high as my chin, and I had no more space into which I might throw the sand, that I might turn round. I made a more desperate effort, drew my body into a ball and turned round. I now faced the stone, which was as wide as the whole passage, but there being an opening at the top I respired fresher air. My next labour was to root away the sand under the stone and let it sink, so that I might creep over, and by this means at length I once more happily arrived in my dungeon.”