TERRESTRIAL PHENOMENA. 1 15 



which is only apparently simultaneous, and however much 

 we may endeavour, by the aid of optical instruments, to 

 bring the mildly-radiant vapour of nebulous masses or the 

 faintly-glimmering starry clusters nearer, and diminish the 

 thousands of years interposed between us and them, that 

 serve as a criterion of their distance, it still remains more than 

 probable, from the knowledge we possess of the velocity of 

 the transmission of luminous rays, that the light of remote 

 heavenly bodies presents us with the most ancient perceptible 

 evidence of the existence of matter. It is thus that the 

 reflective mind of man is led from simple premises to rise to 

 those exalted heights of nature where in the light-illumined 

 realms of space " myriads of worlds are bursting into life, 

 like the grass of the night."* 



From the regions of celestial forms, the domain of Uranus, 

 we will now descend to the more contracted sphere of terres- 

 trial forces to the interior of the Earth itself. A mysterious 

 chain links together both classes of phenomena. According 

 to the ancient signification of the Titanic myth,f the powers 

 of organic life, that is to say, the great order of nature, depend 

 upon the combined action of heaven and earth. If we suppose 

 that the Earth, like all the other planets, prhnordiaily belonged, 

 according to its origin, to the central body, the Sun, and to 

 the solar atmosphere that has been separated into nebulous 

 rings, the same connection with this contiguous Sun, as well 

 as with all the remote Suns that shine in the firmament, is 

 still revealed through the phenomena of light and radiating 

 heat. The difference in the degree of these actions must not 

 lead the physicist, in his delineation of nature, to forget the 

 connection and the common empire of similar forces in the 

 universe. A small fraction of telluric heat is derived from 

 the regions of universal space in which our planetary system 

 is moving, whose temperature (which, according to Fourier, is 

 almost equal to our mean icy polar heat) is the result of the 

 combined radiation of all the stars. The causes that more 

 powerfully excite the light of the Sun in the atmosphere and 

 in the upper strata of our air, that give rise to heat-engen- 



* From my brother's beautiful sonnet " Freiheit und Gesetz." (AVil 

 heinc von Humboldt, Gesammelte Wer/ce, bd. iv. s. 358, No. 25,) 

 t Ottfried MUller, Prolegomena, s. 373. 



