If we see a lovely picture, or a beautiful building, we naturally want to know more about the man who painted the picture or planned the building. Then surely, while searching into the grand distances and glory of the skies, we ought to lift our thoughts in reverent adoration to our Father in Heaven, and to the Son of God, by whom “were all things created that are in heaven and that are in earth.” For “_without Him was not anything made that was made_!” QUESTIONS. 1. Are stars all of the same size? No; some are large and some are small. 2. Are the brightest stars always the largest in size? Not at all. A star may be brighter than another only because it is much nearer. 3. Which is the brightest star in our heavens? Sirius, the Dog-star. 4. Is Sirius as bright as Venus? No; but Venus is a planet, not a star. 5. Is Sirius one of the very largest stars? Sirius is perhaps bigger than our Sun, but not one of the biggest stars. 6. Why, then, is Sirius the brightest? Sirius is one of the nearer stars; not actually near, but far nearer than many others. 7. Is our Sun one of the biggest stars? No; only a moderate-sized star. 8. Tell the names of two giant suns. Arcturus and Capella. 9. Why do we believe Arcturus and Capella to be larger than Sirius? Because they are both very bright stars; and yet they are very much farther away than Sirius. 10. What are Star-Clusters? Clusters of hundreds or thousands of suns, so distant as to seem to us quite close together. 11. What are Nebulæ? Hazy clouds like patches in the sky. 12. What are Nebulæ made of? Some are only great masses of shining gas. Sometimes they are made of stars and gases together. 13. Which are the two brightest Nebulæ? The Nebula in Andromeda and the Nebula in Orion. 14. Tell me the name of a well-known Star-Cluster easily seen? The Pleiades. 15. What do we learn from a photograph of the Pleiades? That some of the stars of this cluster have nebula-gas round them. CHAPTER XXIII. HOW TO STUDY THE SKY. Now I want you to get just a tiny idea of how to _begin_ to find out for yourself a few Planets and Stars in the sky. In one way, the Planets are the easier of the two to find, in another way they are the more difficult. They are easier because they are brighter; at least a few of them are. Also, they do not twinkle. That at once distinguishes them from the Stars. On the other hand they are a little more difficult, because they are always changing their places in the sky. If you learn to know some particular star by sight you will always find that star in the same place among other stars. It may be more to the east or to the west, according to the time of night and of the year; but it will always be in the very same part of the very same star-group. But a planet never keeps long to any particular group of stars. However, after the Sun and Moon, the easiest heavenly bodies of all to find are, no doubt, Venus and Jupiter.