Here, before beginning the assault on the region of precipices, an immense depôt was established. The tunnel was laid down with double lines of the same sort of parallel steel rods as those which I had noticed on the road at Lucetta. On these ran a series of small trucks, driven by an endless chain which was moved by the gas engine beforementioned; and by means of these all the stores required were easily brought up. At the height of fifty thousand feet, which had now been reached, little or no difficulty in breathing was encountered. This was probably owing to the extreme density of the Hesperian atmosphere, which, as was noticed before, is so great that the mercury in the tube of Torricelli, at the sea level, stands at an average height of more than fifty-nine inches. Moreover, the slow rate at which it was observed to fall, during the ascent of the last few thousand feet, gave the engineers good hope that, even at the summit, a sufficiency of air to support life would be found. The ascent of all the three stages of the precipice region was effected by the process of cutting open galleries, inclined at an angle of thirty degrees, in the face of the vertical cliff. The region of ice and snow having been passed, tunnelling was no longer necessary. Four zigzags, each a mile long, sufficed to reach the first terrace, where another depôt was constructed; and a few years’ more labour, and about a dozen similar zigzags, accomplished the ascent of the tremendous middle precipice, thus bringing them within fifteen thousand feet of the cloud-screen. As the great work neared its completion, the anxiety and excitement, not only of those actually engaged in it, but of the entire population of the planet, rose to a scarcely conceivable intensity. It was now plain that the cloud level would be reached; but no light had as yet been thrown on the question whether the mountain top did or did not pass through the cloudy stratum. If it did not, all their labour of years had been merely thrown away, and they were left as before in absolute ignorance of the external universe. And the fact that the ascent which still remained to be scaled, was not absolutely vertical, but, sloping a little, even at its foot on the last terrace, appeared to diminish its inclination as it approached the cloud, gave reason to suspect that the actual summit of the mountain was not very far off. It may be added that the cloud itself, as they came nearer, presented an unpromising appearance of great density.