"That is the case," he said; "but the difference is not such as you suppose. All the material of your bodies is ultimately resolved into ethereal matter, but not all of it is essential to your being, and that which is essential is resolved by a much speedier process.
"But to speak of ourselves: while we remain in our own world we have instruments of sensation fitted to our condition and analogous to yours, just as hearing is analogous to seeing. But I cannot explain to you any more exactly our means of sensation, just as you could not explain sight to a man born blind.
"But our sensations are throughout strictly analogous to yours and pass into yours when we assume terrestrial bodies."
Here he paused again, and I asked, "Can you see our worlds from yours?"
"No," he replied. "The ether as far as we know pervades the universe and passes freely through worlds like yours, and we, while dwelling in the ether, have no more cognisance of your world than you of ours.
"But there are certain links," he added, "which bind both worlds together, and two of these are known to you as light and gravity. Our world is for ever in motion; motion is of the essence of its being, and it