It was discovered, however, that the walls of the barracks consisted of an outer and inner casing, each a foot thick, and built of large sun-dried bricks, the space between being filled up with a mixture of rubble, mortar, and earth, and a few larger stones. This was in the bottom storey. Above that the construction of the wall changed to two thicknesses of lath and plaster attached to either side of a timber framing, and the thickness of the wall diminished to only nine inches. The total width of the wall below was five feet; therefore the lockers in the upper room were immediately above the rubble core of the heavier wall. It would thus be possible to get down through the lockers and sink a shaft through the rubble to a trifle below the level of the ground, and from there to break through the inner casing and come into the empty space below the ground-floor.

Work was commenced in the middle of February 1918. For the next few weeks an officer was usually to be seen lolling about at either end of the first-floor rooms, and, on the approach of an interpreter or other intruder, would stroll leisurely down the passage, whistling the latest ragtime melody.

Within the room all would now be silent; but when the coast was again clear there could perhaps be seen in the barrack room a pair of weird figures, strangely garbed and white with dust. Somewhere in the line of lockers was the entrance to the shaft-head. The locker doors being only a foot square were too small to admit a man, and so the top planks at the place where we wished to work had been levered up and fitted with hinges to form a larger entrance. To give additional room inside, the partition between two consecutive lockers was also removed; the floor of one locker and the joists supporting the platform at this point were then cut away, and we were free to commence the shaft.

For this job six officers were chosen, of whom three belonged to our escape party. The six were divided into three reliefs, and each worked for two hours at a time. The hole was of necessity only just large enough for one man to work there, so of the pair one did the digging, while his partner, when the shaft had progressed a little, sat inside the locker at the top of the hole. When actually at work, the time went quickly enough; but sitting in the locker was very wearisome, as one's only duties were to pass on the alarm when the ragtime was whistled, and from time to time to draw up by a rope the small sacks filled by the digger. When all the available sacks were full, work was stopped, and the two would emerge from the locker. The sacks of rubbish were then carried a few yards along the room and emptied into a space underneath some planks which had been loosened in the platform. At the end of their relief, the two would go off to change their clothes, leaving the work to be continued by the next pair.

During the time spent in the locker, one of the six learnt 'Omar Khayyám' by heart. Reading a book was almost impossible owing to the lack of light; even if it had been permissible, in view of the risk of the reader becoming so interested as to miss the signal of the alarm. 'Omar,' however, was a different thing. A verse could be read line by line at the streak of light entering by a chink in one of the ill-fitting locker doors, and then committed to memory—not a very engrossing task, but it helped to pass the time.

The working kit was a light one: a shirt and "shorts," sand-shoes, and a Balaclava cap. Round his mouth the digger usually tied a handkerchief, so as not to swallow his peck of dust at one time, while the cap prevented his hair and ears getting quite full of rubbish.

Let us work for one relief. You are dressed for the occasion. The tools, consisting of two chisels, are at the bottom of the hole, which is, say, twelve feet deep. A couple of candles and a box of matches is all you need take with you. It is your turn to dig. You get into the locker and climb down the rope-ladder as quickly as possible, but you must take care not to touch the outer casing of the wall as you go, or you may find yourself staring at an astonished sentry outside: there are already a few holes in the wall through which daylight can be seen.

The candle lighted, you have a look round: but this is absurd! No one has done any work since you were down there yesterday morning. That beastly stone in the corner looks as tightly embedded in the mortar as it was then. You bend down to pick up a chisel and you bump your head against a projecting brick. You try to sit down, but there is not enough room to sit and work at the same time. You try kneeling, but it can't be done. After twisting your limbs in a hitherto undreamt-of fashion you begin to chip away at the mortar round your old friend. Nothing seems to happen; then suddenly your candle falls down and goes out, leaving your chamber of little ease in Stygian darkness.

You think you hear your partner say "Stop!" and you look up just in time to get your eyes full of grit, for he has merely shifted his legs, which are dangling above you. After untying yourself you relight the candle and again get down to the stone. You pick and scrape and prise, and then as the chisel slips you bark your knuckles; and so you go on. All sense of time is lost, and your one thought is to get that stone out. Now it moves. You work with redoubled energy, with the result that you break into a profuse perspiration. How you hate that stone! Finally up it comes when you don't expect it, and the bruise at the back of your head is nothing compared to the joy of the victor, which is equally yours.

The rock is too big, however, to go into a sack, so you shut your eyes and whisper to your partner above you. He then lets down an old canvas bath kept in the locker for this purpose. The periphery of the bath is attached to a rope by several cords, the resulting appearance as it is lowered towards you being that of an inverted parachute. The stone is difficult to lift and your feet are very much in the way, but in the end the load is ready. There is not enough room in the shaft for the stone and the bath to be pulled up past your body, so you climb up the ladder and help your partner to haul. This done, work is resumed. A small sack is filled with bits of mortar picked away from round the stone, and this too is pulled up the shaft, but the sack being small you need not leave the hole.