Hercules, Constellation of 338 The Great Bear, Constellation of 341 The Prism and Spectrum 344 The Spectroscope 345 Spectra, Showing the Dark Lines 347 Great Astronomers of Later Times 377 Sir Isaac Newton 386 Eye-piece of Lick Telescope 407 Lick Observatory 409 Professor E. E. Barnard 410 THE STORY OF THE SUN, MOON, AND STARS. CHAPTER I. THE EARTH ONE OF A FAMILY. What is this earth of ours? Something very great--and yet something very little. Something very great, compared with the things upon the earth; something very little, compared with the things outside the earth. And as our journeyings together are for a while to be away from earth, we shall find ourselves obliged to count her as something quite small in the great universe, where so many larger and mightier things are to be found,--if indeed they are mightier. Not that we have to say good-bye altogether to our old home. We must linger about her for a while before starting, and afterwards it will be often needful to come back, with speed swifter than the flight of light, that we may compare notes on the sizes and conditions of other places visited by us. But first of all: what _is_ this earth of ours? It was rather a pleasant notion which men held in olden days, that we--that great and important “We” which loves to perch itself upon a height--stood firm and fixed at the very center of everything. The earth was supposed to be a vast flat plain, reaching nobody could tell how far. The sun rose and set for us alone; and the thousands of stars twinkled in the sky at night for nobody’s good except ours; and the blue sky overhead was a crystal covering for the men of our earth, and nothing more. In fact, people seem to have counted themselves not merely to have had a kind of kingship over the lower animals of our earth, but to have been kings over the whole universe. Sun, stars, and sky, as well as earth, were made for man, and for man only. This was the common belief, though even in those olden days there were _some_ who knew better. But the world in general knows better now. Earth the center of the universe! Why, she is not that of even the particular family in the heavens to which she belongs. For we do not stand alone. The earth is one of a family of worlds, and that family is called THE SOLAR SYSTEM. And so far is our earth from being the head of the family, that she is not even one of the more important members. She is merely one of the little sisters, as it were.