How the Earth acquired an atmosphere and where the oceans came from, have been fascinating problems ever since there were children to ask questions and grown‐ups who couldn't answer them. However, experiments of the physicist and observations of the geologist and the astronomer have furnished the warp and the woof with which the mathematician at last has woven a theory that clothes both these Sphinxes in rare and beautiful raiment.To begin, not truly at the beginning, but as far back as even part‐knowledge permits, we believe that all that we call electricity and all that we call matter consist of two things as yet unresolved—the electron and the proton, the negative and the positive electric" atoms, or at most, these ultimate charges and their carriers. At any rate, these are the most elementary entities of which there is any fairly definite evidence. We have no knowledge of the origin of either the electron or the proton. They can exist separately, from which we infer that they may have originated differently and in different amounts, the excess diffusing itself to infinite rarity. On the other hand, the equality of their charges suggests a common and simultaneous origin. But, be that as it may, they usually are combined in various equal numbers, thereby forming all the material elements from hydrogen to uranium. Hence, wherever matter occurs in great quantity, as in a star or a planet, one may expect to find all the possible elements in varying proportions, and also such compounds of them as the temperature and other conditions favor. Presumably, therefore, every heavenly object, however nebulous or condensed, has within itself, as certainly as our own sun has, the makings of an atmosphere and an ocean. Evidently, then, when the Earth was pulled out of the sun by the tidal action of a passing star of much greater mass, there were taken along the hydrogen, oxygen, and nitrogen of the ocean and the air as well as the iron, silicon, aluminum, and other elements of the lithos