THE HERSCHELS AND THE STAR-DEPTHS. 9 



gaged the earnest attention of astronomers, and should 

 again and again have been referred to or quoted in 

 astronomical treatises. Nor can I greatly wonder that 

 Sir W. Herschel's own confidence should have been 

 shared by those who have presented his theory. 'I 

 have now viewed and gauged the Milky Way,' he says, 

 'in almost every direction, and find it composed of 

 stars whose number, by the account of these gauges, 

 constantly increases and decreases in proportion to its 

 apparent brightness to the naked eye. That this shining 

 zone is a most extensive stratum of stars of various sizes 

 admits no longer of the least doubt, and that our sun 

 is actually one of the heavenly bodies belonging to it is 

 as evident.' 



When to this I add that Sir John Herschel, gauging 

 the depths of the southern heavens, was led to precisely 

 the same conclusions as to the general structure of the 

 Milky Way, it seems impossible not to regard the 

 theory so often presented in our books as involving the 

 definite conclusions of the Herschels respecting the 

 scheme of the fixed stars. Nor is it necessary to add 

 that conclusions thus accepted by the greatest authori- 

 ties in stellar astronomy that have ever lived, must be 

 such as few students of astronomy would care to call in 

 question. 



It will therefore surprise many to be told that, as a 

 matter of fact, seventeen years had not passed after the 

 elder Herschel had enunciated that theory which has 

 been so often presented in astronomical treatises, and 

 which his own son seems always to have regarded as 



