ABSORPTION OF CALORIC BY THE AIR. 73 



divinity " with the awakening of light upon created 

 things. The Egyptian Isis, the Grecian Apollo, who, 



The Lord of boundless light 



Ascending calm o'er the empyrean sails, 



And with ten-thousand beams his awful beauty veils, 



the fire-worshipper of the Persian hills and the sun- 

 god of the Penman mountains, exhibit, through time 

 and space, the full consciousness of man to the influences 

 of solar light and heat upon the organic creations of 

 which he is himself the chief exemplar. 



The investigations of modern philosophers have ex- 

 tended these influences to the inorganic masses which 

 constitute the Planet EARTH : and we now know that 

 the physical forces, ever active in determining the 

 chemical condition and the electrical relations of matter, 

 are directly influenced by the solar radiations. 



Few things within the range of our inquiry are more 

 striking than the phenomena of calorific radiation and 

 absorption. They display so perfectly the most refined 

 system of order, and exhibit so strikingly the admirable 

 adaptation of every formation to its particular con- 

 ditions, and for its part in the great economy of being, 

 that they claim most strongly the study of all who would 

 seek to discover a poetry in the inferences of science. 



Owing to the nature of our atmosphere, we are pro- 

 tected from the influence of the full flood of solar heat. 

 The absorption of caloric by the air has been calculated 

 at about one-fifth of the whole in passing through a 

 column of 6,000 feet. This estimate is, of course, made 

 near the earth's surface ; but we are enabled, knowing 

 the increasing rarity of the upper regions of our gaseous 

 envelope in which the absorption is constantly diminish- 

 ing, to prove, that about one-third of the solar heat is 

 lost by vertical transmission through the whole extent of 

 our atmosphere.* 



* In the Bakerian Lecture for 1842, On the transparency of th* 



