SCIENCE AND POETRY. 



16. In Campbell's immortal poem, the Pleasures of Hope, we 

 find the following lines : 



' ' Angel of Life ! thy glittering wings explore 

 Earth's loneliest bounds, and Ocean's wildest shore. 

 Lo ! to the wintry winds the pilot yields 

 His bark careering o'er unfathom'd fields ; 

 Now on Atlantic waves he rides afar, 

 Where Andes, giant of the western star, 

 With meteor standard to the winds unfurl' d, 

 Looks from his throne of clouds o'er half the world." 



Although it is difficult to assign a limit to the degree of exag- 

 geration allowed by the licence of poetry, it is quite clear that 

 there is some such limit, and we apprehend that if these lines, 

 so admirable as poetry, be curiously examined by the light of 

 science, they will scarcely be considered as falling within such 

 limit. 



We are to imagine with the poet the genius of the Andes 

 enthroned upon the most lofty peak of that chain, looking round 

 him at the hemisphere, on the middle of which his throne rests. 

 To behold from such a position " half the world," would be 

 a manifest optical impossibility, however elevated his seat might 

 be. But if his range of view could in any degree approximate to 

 half, or even to a quarter of the globe, the exaggeration might 

 be allowed to pass. Let us see, however, what would be the 

 utmost possible range of view which could be obtained by an 

 observer placed upon the apex of the most lofty cone of the 

 Andes, supposing the surrounding mountains of less elevation not 

 to interrupt his general view of the earth's surface. 



The most lofty peak of the Andes is that of Aconcagua, which 

 rises immediately above Valparaiso, overlooking the Pacific Ocean. 

 The extreme height of this summit is 23910 feet. Now let us 

 see what would be the extreme range of view from such an 

 elevation ; and in making this calculation we shall, contrary to 



our custom, introduce its mathe- 

 matical details, so as to inspire 

 our readers with greater confidence 

 in the result. Let us suppose the 

 semicircle here indicated to repre- 

 sent the section of the hemisphere, 

 near the middle of which the sum- 

 mit of the mountain is placed. 

 Let represent the base, and T 

 the summit of the mountain. If a line T z be drawn touching 

 the earth, the point z will be the limit of the range of view of 

 an observer looking from T in the direction of T z, and the 

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