“The human race having become dominant on earth, they have entirely overrated their importance and not only fancy that they will some day own the rest of the solar system, but imagine that they will sprout wings and develope into beings like us; but any of you that have studied natural history and your new theories of evolution, ought to know that beings having twelve limbs could never be evolved from a race having but four. The only possible evolution by which your race could ever possess wings, would be the conversion through use and habit of your arms into wings, which has actually occurred in the case of your bats and birds. “The families on earth that are related to and resemble us are the insect tribes. In fact we trace our origin back to an ancestry, which according to many of our best scientists is exactly parallel with that of your insects, and they alone of mundane inhabitants could ever expect to evolve a posterity at all like us, and they never will, for the conditions on earth will forever keep them in a subordinate position to the present dominant race.” During this speech, notwithstanding its intense interest to me I was becoming impatient and nervous with the apprehension that he might leave me without telling me where he was from and how he made that car of his disregard the law of gravitation. In the solution of this last riddle especially I could readily see a utilitarian outcome of overwhelming importance. I am afraid that my questions were put with an undignified eagerness and precipitancy, which no doubt he observed, for he first proceeded to say that he had much information to communicate to me and was glad to see me desirous of receiving it. “You understand the law of the _attraction of_ gravitation”—I nodded assent—“but you know nothing of the _repulsion_ of gravitation.” Indeed I did not. I had never heard of such a thing.