We Never See the Stars. 49 



acutely, so tnat Tennyson was a true exponent of nature when 

 he depicted the eagle in his home — 



"He clasps the crag with hooked hands : 

 Close to the sun in lonely lands, 

 Eing'd with the azure world he stands. 



" The wrinkled sea heneath him crawls ; 

 He watches from his mountain walls, 

 And like a thunderbolt he falls." 



When the sea waves are dwindled down to wrinkles by their 

 distance, the king of birds still perceives upon their shore, 

 objects that would be quite invisible to man ; but there is no 

 reason to believe that even the eye of the eagle has ever 

 " seen the stars." The bird, however, may teach us that with 

 perfect visual organs, remoteness would not prevent the dis- 

 covery of form, but merely reduce its apparent size. 



A distant body must have a certain magnitude, in order 

 that its shape may be visible to any eye, with any particular 

 instrument. The larger the body, the greater the distance at 

 which its shape can be seen, under similar and proportionate 

 illumination, but as the distance increases, the apparent size of 

 any body is rapidly reduced, in conformity with a well-known 

 physical law, so that the mightiest celestial orbs may dwindle 

 through remoteness to the merest specks of light which the 

 eye can discern, and by still farther remoteness, completely 

 elude the power of the largest telescope.* 



We know that the sun's diameter is, according to the best 

 calculations, 850,100 miles, and his distance, by recent deter- 

 mination, about 91,328,600 miles, nearly four hundred times that 

 of the moon. Now the enormous face of the sun, more than one 

 hundred times broader than that of our earth, is eclipsed by a 

 pin's head held near the eye, and it only appears the size of a 

 very small disc held a foot off. Could we pass from our present 

 abode to the more distant planets of the solar system, the 

 great luminary would become smaller and smaller in appear- 

 ance ; and from Neptune, " 30* times the mean distance of the 

 earth from the sun/'f it would look like a mere point of light 

 that would require considerable magnifying to raise into a disc. 

 Mr. Breen tells us that with a power of 150 we can see 

 the appearance of a disc in Neptune " if we consider it atten- 

 tively," and the body which thus requires enlarging to the 

 extent of 150 diameters, or 22,500 times superficially, in 



* An easy mode of illustrating these facts, is to cut a disc, one inch in diameter, 

 and a triangle (with each side equal to the diameter of the circle), of white paper ; 

 stick them against a wall, and walk backwards until the eye fails to see which is 

 the circle and which is the triangle, although two patches of white light will still 

 be discerned. 



t Breen'&Planetary Worlds, page 248. 



VOL. V. — NO. I. F 



