"No, no," I replied with animation. "This fragment of rock has been shaken down by some shock or convulsion, or by one of those magnetic storms which agitate these regions, and has blocked up the passage which lay open to him. Many years have elapsed since the return of Saknussemm to the surface and the fall of this huge fragment. Is it not evident that this gallery was once the way open to the course of the lava, and that at that time there must have been a free passage? See here are recent fissures grooving and channelling the granite roof. This roof itself is formed of fragments of rock carried down, of enormous stones, as if by some giant's hand; but at one time the expulsive force was greater than usual, and this block, like the falling keystone of a ruined arch, has slipped down to the ground and blocked up the way. It is only an accidental obstruction, not met by Saknussemm, and if we don't destroy it we shall be unworthy to reach the centre of the earth." Such was my sentence! The soul of the Professor had passed into me. The genius of discovery possessed me wholly. I forgot the past, I scorned the future. I gave not a thought to the things of the surface of this globe into which I had dived; its cities and its sunny plains, Hamburg and the Königstrasse, even poor Gräuben, who must have given us up for lost, all were for the time dismissed from the pages of my memory. "Well," cried my uncle, "let us make a way with our pickaxes." "Too hard for the pickaxe." "Well, then, the spade." "That would take us too long." "What, then?" "Why gunpowder, to be sure! Let us mine the obstacle and blow it up." "Oh, yes, it is only a bit of rock to blast!" "Hans, to work!" cried my uncle. The Icelander returned to the raft and soon came back with an iron bar which he made use of to bore a hole for the charge. This was no easy work. A hole was to be made large enough to hold fifty pounds of guncotton, whose expansive force is four times that of gunpowder. I was terribly excited. Whilst Hans was at work I was actively helping my uncle to prepare a slow match of wetted powder encased in linen. "This will do it," I said. "It will," replied my uncle. By midnight our mining preparations were over; the charge was rammed into the hole, and the slow match uncoiled along the gallery showed its end outside the opening. A spark would now develop the whole of our preparations into activity. "To-morrow," said the Professor. I had to be resigned and to wait six long hours. CHAPTER XLI. THE GREAT EXPLOSION AND THE RUSH DOWN BELOW The next day, Thursday, August 27, is a well-remembered date in our subterranean journey. It never returns to my memory without sending through me a shudder of horror and a palpitation of the heart. From that hour we had no further occasion for the exercise of reason, or judgment, or skill, or contrivance. We were henceforth to be hurled along, the playthings of the fierce elements of the deep.