Jules Verne

“ Some days we advanced nearer to the centre by a league and a half, or nearly two leagues. These were perilous descents, in which the skill and marvellous coolness of Hans were invaluable to us. That unimpassioned Icelander devoted himself with incomprehensible deliberation; and, thanks to him, we crossed many a dangerous spot which we should never have cleared alone.
But his habit of silence gained upon him day by day, and was infecting us. External objects produce decided effects upon the brain. A man shut up between four walls soon loses the power to associate words and ideas together. ”

“ Chapter XXVI The Worst Peril Of All It must be confessed that hitherto things had not gone on so badly, and that I had small reason to complain. If our difficulties became no worse, we might hope to reach our end. ”