II 



appreciable disk. We may safely infer, from many 

 observations of recent years, that thousands of the 

 stars are almost identical in character with the 

 sun, though some are much larger or smaller and 

 some are in earlier or later stages of development. 

 But if we wish to know what a star really is we 



FIG. 5. Direct photograph of the Sun. 



must approach it closely, and this is possible only 

 in the case of the sun. Indeed, because the sun 

 was regarded as so important, offering so many 

 opportunities to increase our knowledge of its 

 nature, the observatory was conceived primarily 



