"We are all unwell, if it comes to that," Newton returned, "for if some Plague were to take us all, why, these little spectra would still crawl about the room until the End of Days, neither knowing nor caring whether living hands were held up to catch them. Our flesh stops the light. The flesh is weak, yes, but the spirit is strong, and by applying our minds to the contemplation of what has been interrupted by our fleshly organs of sense, we may make our minds wiser and our spirits better, even though flesh decays. Now! I do not have a fever, my lady." He took his hand back, and gripped the arm of his chair to stop its shivering. The little rainbow now fell on Eliza’s cupped hands. "But I am mortal and would fain do all that I could, in the time allotted to me, to penetrate this mystery of Force. Now consider this light that you are catching in your hands. It has traveled a hundred million miles from the Sun without being affected in any wise by the Cœlestial Æther. In its passage through the atmosphere it has been subjected to only slight distortions. And yet in traversing a quarter of an inch of window-glass, its course is bent, and it is riven into several colors. It is such an everyday thing that we do not mark it; yet pray consider for a moment just how remarkable it is! During its hundred-million-mile passage, is it not acted upon by the gravity of the Sun, which is powerful enough to hold even mighty Jupiter in its grasp, though at a much greater remove? And is it not acted upon as well by the gravity of the Earth and Moon, and all the other planets? And yet it seems perfectly insensitive to thse mighty forces. Yet there is embedded within this shard of glass some hidden Force that bends it and splits it with no effort. It’s as if a cannonball, hurled at infinite speed from some gun of inconceivable might, and passing through ramparts and bulwarks as if they were shadows, were deflected and shivered into bits by a child holding up a feather. What could be concealed within an ordinary piece of window-glass that harbors such potency, and yet affects you and me not at all? Or consider the action of acids, which can in a few moments dissolve stones that have stood unmarked by Time and the elements since the world was formed. What has the power to annihilate a stone God made, a stone that could support a Pyramid, stop fire, or turn aside musket-balls? Some force of immense power must be latent in acids, to destroy what is so strong. And is it so inconceivable that this force might be akin to, or the same as, what bends the light as it passes through the window? Are these not perfectly suitable questions to be asked by those who style themselves Natural Philosophers?"