If I listed every trouble I've accumulated in a mere two hundred odd years you might be inclined to laugh. When a tale of woe piles up too many details it looks ridiculous, unreal. So here, at the outset, I want to say my life has not been a tragic one—whose life is in this day of advanced techniques and universal good will?—but that, on the contrary, I have enjoyed this Earth and Solar System and all the abundant interests that it has offered me. If, lying here beneath these great lights, I cou