Yet that the Peoples of the _Upper_ Cities had great chests, I do well know; for this was a common knowledge; even as we of this age do acknowledge the Peoples of Africa to be of blackness, or those of Patagonia to be of great stature. And by this one thing should any know a man of the Upper Cities, from a man of the Lower Cities. And because that there grew this difference among the Peoples, there had been once, as any could learn from the Histories, a plan whereby the Peoples should be moved upward and downward through the great height of the Mighty Pyramid, from this city unto that. Yet had it met with great disfavour; and was put out of force; and this is easy to be seen as the natural way of the human heart. And here it doth occur unto me that it was like enough to be a plan for health, beside of training of the mind, that each youth and maid was put to travel through all the cities of the Mighty Pyramid; the which did take three years and two hundred and twenty-five days, as I have told before this. For by this plan, were they made to breathe the air of every height, and this, mayhaps, unto the good of their developing. And they also to discover that air which was best to their need. And concerning the air of the Night Land, you shall know that there was in all that Land no flying thing, because that the air was grown very thin; yet, as the Records did show, there had once been monstrous flying-brutes, that went over the Land in mighty bounds; but this was in a long gone age; and we could but suppose that the Records gave truth. And here you shall know that, when the Monstruwacans did learn that I would journey through the Night Land, in search of Naani, there had been some foolish and well-intended talk among them that I take a small flying-ship, that was in the Great Museum beside the models of the Great Ships. For, truly, this machine was yet sound to go; for it was made of the grey metal of the Mighty Pyramid, that did seem to have no power to cease. Yet, in verity, I had no skill to manage this, neither had it flown, through an hundred thousand years; so that none did know the mastership of that art, which did be learned but by a constant practice, and oft made uneasy by fallings that did wreck the machine, as I did know from the Book of Flying. And, moreover, as I have told, the air of the Night Land was grown over-weak to uphold such a thing; which, I doubt not, had made the Peoples of the Pyramid to cease from flyings, quite so much as that they did fear the Forces of Evil in the night. And if that there had been air and skill sufficient unto this purpose of flying, yet had I been wicked with foolishness that I should work to be hung upward in the night, for all the Evil of the Night Land to behold. And though I had gone up some great way, yet the machine had surely made a great noise in the quietness of the eternal night, as you shall suppose.