John Smith, then, whom I know very well, and greatly esteem, and who is approaching middle age, had, about 34 years ago, two ancestors. About 102 years ago, say in the year of grace 1792, he had eight—though he did not have himself. You can do the rest of the figuring yourself if you care to go on and are unwilling to take my word for what follows—the astonishing state of things which I am about to thrust upon your attention. Just keep doubling the number of John Smith’s ancestors until you get the number 1,073,741,824. Now when do you suppose it was that Mr. Smith had that number of living ancestors? Make your calculation, allowing 34 years for each time that you have multiplied by two, and you will find that it was about the year 879. It seems a rather modern date and a goodish number of persons to be concerning themselves, however unconsciously, in the begetting of Neighbor John, but that is not “where it hurts.” The point is that the number of his ancestors, so far as we have gone, is about the number of the earth’s inhabitants at that date—little and big; white, black, brown, yellow and blue; males, females and girls. I do not care to point out Mr. Smith’s presumption in professing himself an Anglo-Saxon—with all that mixed blood in the veins of him; perhaps he has never made this calculation and does not know from just what stock he has the honor to have descended, though truly this distinguished scion of an illustrious race might seem to be justified in calling himself a Son of Earth. But is he not more than that? In the generation immediately preceding the one under consideration the number of the gentleman’s ancestors must have been twice as great, namely, 2,147,483,648—more than two thousand millions, or some five hundred millions more than Earth is infested with even now. Where did all those people live?—in Mars? And to what political or other causes was due the migration to Earth, _en masse_, of their sons and daughters in the next generation? Does the reader care to follow up Mr. Smith’s long illustrious line any further—back to the wee, sma’ years of the Christian era, for example? Well and good, but I warn him that geometrical progression, as he has already observed, “counts up.” Long before his calculations have reached back to the first merry Christmas he will find Mr. Smith’s ancestors—if they were really all terrestrial in their habits—piled many-deep over the entire surface of all the continents, islands and ice-floes of this distracted globe. A decent respect for the religious convictions of my countrymen forbids me even to hint at what the calculation would show if carried back to the time of Adam and Eve.