'IN DESCRIPTIVE ASTRONOMY. 127 



49. Is there ever an annular eclipse of the moon ? 



(See Astronomy, p. 146.) 



50. " While the sun rises and sets 365 times, a star 

 rises and sets 366 times." Explain. 



/, p. 264.) 



51. How many moons are there in the solar system ? 



Twenty have been discovered. 



52. What causes the twinkling of the stars ? 



(See Astronomy, p. 207.) 



Some attribute the twinkling of the stars to the inequality 

 of refraction due to the constant changes in the density of the 

 air, produced by the constant changes in the heat. 



53. Name some of the uses of the stars. 



(See Astronomy, pp. 212, 285.) 



54. Describe the methods by which we determine the 

 distance of the sun from the earth. 



(See Astronomy, p. 275.) 



55. Why do not the signs and the constellations of the 



Zodiac agree ? 



(See Astronomy, pp. 106, 211.) 



56. Wlien we look at the North Star, how long since the 

 light that enters our eye has left that body ? 



(See Astronomy, p. 218.) 



57. In what direction does a comet's tail generally 



point ? 



(See Astronomy, note, p. 306.) 



58. What is the cause of shooting stars ? 



(See Astronomy, p 182.) 



59. Why does the crescent moon appear larger than 

 the dark body of the moon ? 



(See Astronomy, p. 123.) 



60. THiat is the real path of the moon ? 



(See Astronomy, pp. 123, 301.) 



61. What ^vould be the result if the aocis of the earth 

 were parallel to the plane of its orbit ? 



(Sec Astronomy, Article xx., p. 103.) 



