CONTENTS. 



i. THE HEAT OF THE SUN 1 



H. EXPENDITURE AND SUPPLY . . . .15 

 in. How THE HEAT is KEPT UP .... 26 

 iv. WHAT WE OWE TO THE SUN .... 40 

 v. THE CONSTANT FACE OF THE MOON ... 49 

 vi. THE MOON'S HISTORY ..... 63 



vn. THE LUNAR WORLD 77 



vm. A VISIT TO AN OBSERVATORY . . .97 



ix. AN EVENING WITH THE TELESCOPE . . .113 



x. NOTES ON NEBULA 124 



xi. VENUS AND MERCURY . . . 141 



xn. MARS AS A WORLD 149 



xni. THE GREATEST PLANET 180 



xiv. THE NAMES OF THE PLANETS . . . .195 

 xv. A FALLING STAR . . 202 



