302 GEOLOGIES AND DELUGES 



its life will cease, and it will become numbered amongst 

 the dead planets. 



A good deal of this "uniformitarian geology might 

 perhaps itself have guessed, had it extended its views 

 beyond rocks and fossils to the stars and other shining 

 bodies which people the vast realms of space. The 

 present, then, strange to say, will still afford a key to 

 the past. We have but to turn to the sun, our nearest 

 luminary, though still more than ninety millions of miles 

 away from us, and in that great orb we find much to sug- 

 gest the state of our planet some ninety millions of years 

 ago or more. It is scarcely necessary to remind you of the 

 fact that the sun is a body so hot that the most refractory 

 substances known to us on the earth exist in it in a 

 state of gas or vapour ; tongues of glowing gas shoot 

 from it like flames ; the clouds which emit its brilliant 

 light are probably clouds of carbon or silicon, which 

 have momentarily condensed from a gaseous state ; and 

 rain, if rain ever occurs, must be a rain of molten metals 

 such as iron, which will be dissipated in gas before it has 

 fallen very far. 



If we proceed to the more remote nebulae, largely 

 composed of glowing masses of gas, we find a suggestion 

 of a stage more embryonic still, when the earth had as yet 

 no separate existence, but formed, with its sister planets 

 and the sun, a single shining cloud. 



On the other hand, if we turn our gaze on our nearest 

 relative offspring possibly that dead planet, the moon, 

 we may read in its pallid disc the sad reminder, " Such as 

 I am, you, too, some day will be." 



But this was not all that was contained in the admoni- 

 tion of physics ; it showed not only that the earth is 

 mortal, but that its span of life, as measured in years, 

 or millions of years, is brief compared to the almost 

 unlimited periods which geology had been in the habit 



