GAMMA VIRGINIS 225 



this when he stood in wondering awe before the hole 

 in the heavens. 



That Herschel fell into mistakes regarding double 

 stars cannot and need not be denied. It was unavoid- 

 able that the first traveller in an unexplored region, 

 billions of miles distant from our earth, should err in 

 tracing paths, measuring time, and estimating dis- 

 tances. He failed in his calculations with y Virginis, 

 which he represented as two companions that revolved 

 round a common centre in 708 years. His son by a 

 careful discussion of the observations made since 1718 

 showed that the time of revolution was not 708 years 

 but 513. It was also predicted that the smaller of the 

 two companions would reach the point where it is 

 nearest the larger in the beginning of 1834. Even 

 these revised calculations proved to be incorrect, for 

 it did not reach that point till two years later. 

 Observations of the star were then renewed for 

 several years; new calculations were made, and the 

 time of revolution of the lesser companion round the 

 greater was found to be 182 years. But it came out 

 that the orbit of 1834, with the time 513 years, was 

 nearly the same, in part of its course, as the true orbit, 

 and was " a curious example, and by no means the first 

 in the history of the progress of discovery, where of 

 two possible courses, each at the moment equally 

 plausible, the wrong has been chosen." 1 



But Herschel's study of the fixed stars and of the 

 unity of plan in nature went farther than we have 

 yet traced. A paper read by him in 1814 contains 

 the following facts, that might almost have been pro- 

 phecies of wonders in store for men " Stars although 



1 Edin. Xev. t 1848, 132-33. 

 15 



