On this day for several hours I used my pickaxe vigorously. The work kept me up. Besides, to work was to quit the _Nautilus_, and breathe directly the pure air drawn from the reservoirs, and supplied by our apparatus, and to quit the impoverished and vitiated atmosphere. Towards evening the trench was dug one yard deeper. When I returned on board, I was nearly suffocated by the carbonic acid with which the air was filled—ah! if we had only the chemical means to drive away this deleterious gas. We had plenty of oxygen; all this water contained a considerable quantity, and by dissolving it with our powerful piles, it would restore the vivifying fluid. I had thought well over it; but of what good was that, since the carbonic acid produced by our respiration had invaded every part of the vessel? To absorb it, it was necessary to fill some jars with caustic potash, and to shake them incessantly. Now this substance was wanting on board, and nothing could replace it. On that evening, Captain Nemo ought to open the taps of his reservoirs, and let some pure air into the interior of the _Nautilus;_ without this precaution we could not get rid of the sense of suffocation. The next day, March 26th, I resumed my miner’s work in beginning the fifth yard. The side walls and the lower surface of the iceberg thickened visibly. It was evident that they would meet before the _Nautilus_ was able to disengage itself. Despair seized me for an instant; my pickaxe nearly fell from my hands. What was the good of digging if I must be suffocated, crushed by the water that was turning into stone?—a punishment that the ferocity of the savages even would not have invented! Just then Captain Nemo passed near me. I touched his hand and showed him the walls of our prison. The wall to port had advanced to at least four yards from the hull of the _Nautilus_. The Captain understood me, and signed me to follow him. We went on board. I took off my cork-jacket and accompanied him into the drawing-room. “M. Aronnax, we must attempt some desperate means, or we shall be sealed up in this solidified water as in cement.” “Yes; but what is to be done?” “Ah! if my _Nautilus_ were strong enough to bear this pressure without being crushed!” “Well?” I asked, not catching the Captain’s idea. “Do you not understand,” he replied, “that this congelation of water will help us? Do you not see that by its solidification, it would burst through this field of ice that imprisons us, as, when it freezes, it bursts the hardest stones? Do you not perceive that it would be an agent of safety instead of destruction?” “Yes, Captain, perhaps. But, whatever resistance to crushing the _Nautilus_ possesses, it could not support this terrible pressure, and would be flattened like an iron plate.”