First and Last Things by H.G. Wells — Read

I would like in a parenthetical section to expand and render rather more concrete this idea of the species as one divaricating flow of blood, by an appeal to its arithmetical aspect. I do not know if it has ever occurred to the reader to compute the number of his living ancestors at some definite date, at, let us say, the year one of the Christian era. Everyone has two parents and four grandparents, most people have eight great-grandparents, and if we ignore the possibility of intermarriage we shall go on to a fresh power of two with every generation, thus: --

Column 1: Number of generations.