160 TH WOULD. / 



blue of the sky, and the bright azure which tinges the distant 

 mountains when viewed through a considerable body of inter- 

 vening air, and especially, when charged with watery vapor 

 Perhaps this one feature., which so mellows down the distant out- 

 lines of the hills and buildings, is the most pleasing feature of 

 the landscape. It is from strict attention to the phenomena de- 

 pendent upon this principle, that the artist derives his pleasing 

 skill in picturing objects of varying distance, introducing skill- 

 fully the color of the intervening air. How simple, and yet how 

 beautiful are the various contrivances which administer, not to 

 the wants merely, but to the pleasures of man. It is the same 

 simple cause which tints the bright blue sky, and its beautiful 

 clouds, here piled in snowy masses, and there sundered into a 

 thousand fleecy shapes; which lights the west with a golden glow 

 and fringes the extended clouds that skirt the horizon with the 

 brightest hues of red and gold ; and it is owing to the peculiar 

 nature of the red rays of the spectrum, that the sun appears a 

 dull red globe when viewed through air highly saturated with 

 watery vapor, or through clouds and fogs. 



When the rays of the sun strike upon a cloud, they are copi- 

 ously reflected, but partly absorbed by the minute suspended glo- 

 bules, and the quantity of light which penetrates through the 

 nebulous medium is always much less than what traverses an 

 equal body of air, and this gives the clouds their varying shades 

 of color. That the color of the sky is owing to reflected light, is 

 sufficiently evident from the fact, that it becomes darker and 

 darker, as we ascend into the higher regions of the atmosphere, 

 through which, the blue rays find a ready passage. Were it not 

 for the reflecting power of the atmosphere, and the clouds, we 

 would have no softening of the day into night, as now, by the 

 twilight; but instantly, at sunset, darkness would veil the earth, 

 and every cloud that obscured the sun would cause a total eclipse. 

 The tint of the sky is deeper in the torrid zone than in high lati- 

 tudes, and in the same parallel it is fainter at sea than on land, 

 this may be attributed to the aqueous vap'or continually rising 

 towards the higher regions of the" air from the surface of the sea. 

 The presence of much moisture is also easily detected by the 



