"Now sixteen is the hundredth part of our contemplated expedition. If we go on in this way we shall be two thousand days, that is about five years and a half, going down." The Professor folded his arms, listened, but did not speak. "Without counting that if a vertical descent of sixteen leagues costs us a horizontal of eighty-five, we shall have to go about eight thousand leagues to the southeast, and we must therefore come out somewhere in the circumference long before we can hope to reach the centre." "Bother your calculations," cried my uncle in one of his old rages. "On what basis do they rest? How do you know that this passage does not take us direct to the end we require? Moreover, I have in my favor, fortunately, a precedent. What I have undertaken to do, another has done, and he having succeeded, why should I not be equally successful?" "I hope, indeed, you will, but still, I suppose I may be allowed to--" "You are allowed to hold your tongue," cried Professor Hardwigg, "when you talk so unreasonably as this." I saw at once that the old doctorial Professor was still alive in my uncle--and fearful to rouse his angry passions, I dropped the unpleasant subject. "Now, then," he explained, "consult the manometer. What does that indicate?" "A considerable amount of pressure." "Very good. You see, then, that by descending slowly, and by gradually accustoming ourselves to the density of this lower atmosphere, we shall not suffer." "Well, I suppose not, except it may be a certain amount of pain in the ears," was my rather grim reply. "That, my dear boy, is nothing, and you will easily get rid of that source of discomfort by bringing the exterior air in communication with the air contained in your lungs." "Perfectly," said I, for I had quite made up my mind in no wise to contradict my uncle. "I should fancy almost that I should experience a certain amount of satisfaction in making a plunge into this dense atmosphere. Have you taken note of how wonderfully sound is propagated?" "Of course I have. There can be no doubt that a journey into the interior of the earth would be an excellent cure for deafness." "But then, Uncle," I ventured mildly to observe, "this density will continue to increase." "Yes--according to a law which, however, is scarcely defined. It is true that the intensity of weight will diminish just in proportion to the depth to which we go. You know very well that it is on the surface of the earth that its action is most powerfully felt, while on the contrary, in the very centre of the earth bodies cease to have any weight at all." "I know that is the case, but as we progress will not the atmosphere finally assume the density of water?" "I know it; when placed under the pressure of seven hundred and ten atmospheres," cried my uncle with imperturbable gravity. "And when we are still lower down?" I asked with natural anxiety. "Well, lower down, the density will become even greater."