"Do you know," I interrupted, "that if these statements were made to men they would not be credited? Scientific men have calculated the weights of the planets, and have estimated therefrom the density of the earth, showing it to be solid, and knowing its density, they would, on this consideration alone, discredit your story concerning the earth shell." [Illustration: THE EARTH AND ITS ATMOSPHERE. The space between the inner and the outer lines represents the atmosphere upon the earth. The depth to which man has penetrated the earth is less than the thickness of either line, as compared with the diameter of the inner circle.] "You mistake, as you will presently see. It is true that man's ingenuity has enabled him to ascertain the weights and densities of the planets, but do you mean to say that these scientific results preclude the possibility of a hollow interior of the heavenly bodies?" "I confess, I do." "You should know then, that what men define as density of the earth, is but an average value, which is much higher than that exhibited by materials in the surface layers of the earth crust, such as come within the scrutiny of man. This fact allows mortals of upper earth but a vague conjecture as to the nature of the seemingly much heavier substances that exist in the interior of the earth. Have men any data on hand to show exactly how matter is distributed below the limited zone that is accessible to their investigations?" "I think not." "You may safely accept, then, that the earth shell I have described to you embraces in a compact form the total weight of the earth. Even though men take for granted that matter fills out the whole interior of our planet, such material would not, if distributed as on earth's surface, give the earth the density he has determined for it." "I must acquiesce in your explanations." "Let us now go a step further in this argument. What do you imagine is the nature of those heavier substances whose existence deep within the earth is suggested by the exceedingly high total density observed by man on upper earth?" "I am unable to explain, especially as the materials surrounding us here, seemingly, do not differ much from those with which my former life experience has made me acquainted." "Your observation is correct, there is no essential difference in this regard. But as we are descending into the interior of this globe, and are approaching the central seat of the shell of energy, the opposing force into which we plunge becomes correspondingly stronger, and as a consequence, matter pressed within it becomes really lighter. Your own experience about your weight gradually disappearing during this journey should convince you of the correctness of this fact." "Indeed, it does," I admitted.