IT has often been said that the history of the race is that of the individual writ large, and this remark is specially applicable to the question of the size of the universe. The new-born child is unable to form an adequate conception of the size of the world, probably because it takes its cradle or its nursery as its unit of measurement. It was the same with the human race in its infancy. Taking for granted that the earth was the central and most important part of the universe, it somewhat naturally supposed that the earth was comparable in size with the whole universe.