CHAPTEE IX. 



THE STARS. 



THE most remarkable progress in astronomy 

 during the past century has been in the de- 

 partment of sidereal science, or the study of 

 the Suns of space, observed for their own sakes, 

 and not merely for the purpose of determining 

 the positions of the Sun and Moon, and to assist 

 navigation. Thanks to Herschel, the nineteenth 

 century witnessed the steady development of 

 stellar astronomy, combined with many import- 

 ant discoveries and investigations. 



The one pre - Herschelian problem in sidereal 

 astronomy was the distance of the stars. Owing 

 to its bearing on the Copernican theory, the 

 problem was attacked by the astronomers of the 

 seventeenth and eighteenth centuries. Herschel 

 made numerous attempts to detect the parallax 

 of the brighter stars, but failed. Meanwhile 

 there had been many illusions. Piazzi believed 

 that his instruments which in reality were 



