"It is supposed by your surface men that the maximum of weight is to be found at one-sixth the distance beneath the surface of the earth, and therefrom decreases until at the center it is nothing at all," he replied. "This hypothesis, though a stagger toward the right, is far from the truth, but as near as could be expected, when we consider the data upon which men base their calculations. Were it not for the purpose of controverting erroneous views, men would have little incentive to continue their investigations, and as has been the rule in science heretofore, the truth will, in time, appear in this case. One generation of students disproves the accepted theories of that which precedes, all working to eliminate error, all adding factors of error, and all together moving toward a common goal, a grand generalization, that as yet can not be perceived. And still each series of workers is overlooking phenomena that, though obvious, are yet unperceived, but which will make evident to future scientists the mistakes of the present. As an example of the manner in which facts are thus overlooked, in your journey you have been impressed with certain surprising external conditions, or surroundings, and yet are oblivious to conditions more remarkable in your own body. So it is with scientists. They overlook prominent facts that stare them boldly in the face, facts that are so conspicuous as to be invisible by reason of their very nearness." "This statement I can not disprove, and therefore must admit under protest. Where there is so much that appears mysterious I may have overlooked some things, but I can scarcely accept that, in ignorance, I have passed conditions in my own organization so marked as this decrease in gravity which has so strikingly been called to my attention." "You have, and to convince you I need only say that you have nearly ceased to breathe, and are unconscious of the fact." I stopped short, in momentary alarm, and now that my mind was directed to the fact, I became aware that I did not desire to breathe, and that my chest had ceased to heave with the alternate inhalation and exhalation of former times. I closed my lips firmly, and for a long period there was no desire for breath, then a slight involuntary inhalation followed, and an exhalation, scarcely noticeable, succeeded by a great interval of inaction. I impulsively turned my face toward the passage we had trod; a feeling of alarm possessed me, an uncontrollable, inexpressible desire to flee from the mysterious earth-being beside me, to return to men, and be an earth-surface man again, and I started backward through the chamber we had passed. The guide seized me by the hand, "Hold, hold," he cried; "where would you go, fickle mortal?"