SIR JOHN FREDERICK WILLIAM HERSCHEL. 133 



These principles Sir John Herschel strictly observed. He approached 

 every subject on which he proposed to theorize with " enforced mental 

 purity." He divested himself of prejudice. Previous views, precon- 

 ceived notions, pride of oi)inion were cast aside. Like a child, he went to 

 Nature's school to learn what she had to teach. When he entered on 

 his astronomical labors, double stars were supposed to be two stars seen 

 ace id entail}/ in the same direction, and his lather had propounded the 

 grandest views respecting galaxies beyond our own. Sir John Her- 

 schel must have regarded these two theories with great favor, for they 

 were associated with the name of his father. Notwithstanding this. Sir 

 John devoted twenty-one years — eight in resurveying the fields of 

 space which had been swept by his father's telescope, four in observa- 

 tion of the southei'u heavens, and nine in reducing his work to form 

 — in order to confirm or overturn, as facts might warrant, these hypo- 

 theses of his father. From him we now know that double stars are not 

 stars seen accidentally in tlie same direction, but are star-couples, asso- 

 ciated by the mighty bond of common gravity. We also know that the 

 second hypothesis did not bear the crucial test to which it was subjected. 

 Other theories, indeed, of the elder Herschel, in their important feat- 

 ures, were confirmed. It is not of that, however, that we speak, but 

 of the conscientious honesty and philosophic spirit with which the son 

 reviewed and continued his father's work, forever setting scientific 

 truth higher than filial reverence. 



Sir John Herscliel was most sagacious in the interpretation of facts. 

 Take, for example, his examination of the Magellauic clouds, those two 

 curious patches on the southern celestial vault. He mapped their out- 

 lines, pictured their minute stars, and colored and shaded their star- 

 cloudlets. At this point others might have stopped. There was an 

 array of interesting objects in certain regions of the heavens. What 

 more could he say ? But Sir John Herschel was not thus satisfied. He 

 reasoned from the globular shape of the JMagellanic clouds to the dis- 

 tance of the star-cloudlets within them, thence to the scale on which 

 they were formed, and thus deduced the most im])ortant conclusion, 

 perhaps, ever arrived at in astronomy by abstract reasoning, to wit, that 

 all the orders of star-cloudlets belong to our oicn system. 



Again, Sir John Herschel was deeply impressed with the existence of 

 analogies throughout the whole range of creation. In a private letter 

 written to Eichard A. Procter, as late as 1800, we find him saying : 

 "An opinion which the structure of the Magellanic clouds has often 

 suggested to me, has been strongly recalled by what you say of the 

 inclusion of every variety of nebulous form within our galaxy, viz, that 

 if such be the case, that is, if these forms belong to the galactic system, 

 then that system includes within itself miniatures of itself on an almost 

 infinitely reduced scale, and what evidence then have we that there 

 exists a universe beyond, unless a sort of argument from analogy, that 

 the galaxy, with all its contents, may be hut one of these miniatures of 



