456 CONCLUSION. [SECT, xxxvm. 



and properties of the sunbeam, the mode of its propagation 

 through the ethereal fluid, or in the interior of material 

 bodies, and the origin of colour. By the eclipses of Jupiter's 

 satellites the velocity of light is ascertained ; and that ve- 

 locity, in the aberration of the fixed stars, furnishes the 

 only direct proof of the real motion of the earth. The 

 effects of the invisible rays of light are immediately con- 

 nected with chemical action ; and heat, forming a part of 

 the solar ray, so essential to animated and inanimated ex- 

 istence, whether considered as invisible light or as a distinct 

 quality, is too important an agent in the economy of crea- 

 tion not to hold a principal place in the connexion of 

 physical sciences; whence follows its distribution in the 

 interior and over the surface of the globe, its power on the 

 geological convulsions of our planet, its influence on the 

 atmosphere and on climate, and its effects on vegetable and 

 animal life, evinced in the localities of organized beings on 

 the earth, in the waters, and in the air. The connexion of 

 heat with electrical phenomena, and the electricity of the 

 atmosphere, together with all its energetic effects, its 

 identity with magnetism and the phenomena of terrestrial 

 polarity, can only be understood from the theories of these 

 invisible agents, and are, probably, identical with, or at 

 least the principal causes of, chemical affinities. Innu- 

 merable instances might be given in illustration of the 

 immediate connexion of the physical sciences, most of which 

 are united still more closely by the common bond of analysis, 

 which is daily extending its empire, and will ultimately 

 embrace almost every subject in nature in its formulae. 



These formulae, emblematic of Omniscience, condense into 

 a few symbols the immutable laws of the universe. This 

 mighty instrument of human power itself originates in the 

 primitive constitution of the human mind, and rests upon a 

 few fundamental axioms, which have eternally existed in 

 Him who implanted them in the breast of man when He 

 created him after His own image. 



