CONTENTS 



PROCTOR, RICHARD A. 



WHAT WE LEARN FROM THE SUN 



Vast size of the Sun. Its spots and their significance, 

 their variations affect the magnetism of the earth. 

 The spectroscope shows that the sun and the earth 

 are built of much the same elements. Theories of the 

 origin of solar heat ...3 



NEWCOMB, SIMON 



THE PROBLEMS OF ASTRONOMY 



What are the distances of the fixed stars? Do the 

 farthest stars within our view mark the boundary of 

 the material universe ? Has the uni verse had a limited 

 or an eternal past? 33 



YOUNG, CHARLES A. 



THE ASTRONOMICAL OUTLOOK 



An astronomical lens of Jena glass brings all the diverse 

 rays of an image to a single focus, an effect never at- 

 tained before. Photography may yet replace the eye 

 in every task of celestial observation. New mathe- 

 matical methods needed. New instruments may 

 increase the completeness and accuracy of observation. 53 



ILES, GEORGE 



THE PHOTOGRAPHY OF THE SKIES 



The beginnings by Dr. Draper and Professor Bond. 

 Freehand drawing untrustworthy in picturing eclipses, 

 xix 



