330 HUMBOLDT'S COSMOS : 



Bessel, Struve, Sir J. Herschel, and Argelander, in prosecu- 

 tion of the same question, as among the loftiest efforts of 

 astronomical science ; and almost as striking in the methods 

 pursued as in the results obtained. They define the power 

 of that wonderful organ the human eye, over objects in a 

 depth of distance which the human imagination strives vainly 

 to reach; they indicate the increase of power gained by 

 artificial instruments of vision; they show the relative 

 depths in space at which luminous worlds are visible to us ; 

 and they explain those irregularities which arise from the 

 structure of the eye and imperfect methods of its use ; from 

 the faults of instruments ; from atmospheric conditions ; and, 

 finally, from the properties of that marvellous element of 

 light itself.* 



It is easy to enumerate these particulars, but hard to 

 convey an idea of the grandeur of the objects which are thus 

 brought within the scope of human research, and of the 

 speculations legitimately derived from them. When we are 

 led to believe, on reasons scarcely admitting of refutation, 

 that there are stars made visible to us, the light of which 

 reaching our telescopes at any given moment, must have 

 been emitted from these stars nearly 2,000 years ago, the 

 result is one which no language can duly denote, and of which 

 the simplest expression is the most sublime. Were it not for 

 that infirmity of man's present state which is ever dragging 

 him downwards to the things of the earth, it might seem 

 impossible for the astronomer, who has lived and laboured 



which, any one wishing to gain knowledge of these remarkable researches, will 

 do well to study throughout. 



* We may mention as an example of the singular and unexpected results 

 obtained by these researches, the discovery of Struve that a telescope admitting 

 no more light than the simple pupil of the eye, does actually show nearly twice 

 as many stars in a given space as are seen by the eye alone. This curious fact 

 renders necessary a correction of Sir W. Herschel's view of the proportionate 

 distance of stars visible to the naked eye, and telescopic stars. 



