Chemical Geology. By Charles Ekin, F.C.S. 

 Mead Feb. 2Uh, 1869. 



The recent discoveries by means of the spectroscope, as to the 

 physical constitution of the sun, stars and nebulte, render this not 

 an inappropriate time to review, what we know and what we may 

 fairly conjecture, of the infant stage of our own globe, and my 

 endeavour will be to set before you as clearly as I can this evening, 

 the opinions now generally held by our best scientific authorities 

 on the subject. 



A subject that embraces not only a consideration of the sciences 

 of chemistry and geology, but also to some extent of astronomy and 

 physics, and which traces the history of the world from the time 

 when it existed in space in common with the other planets and the 

 sun, as a mere congregation of gases, through its several stages, 

 to the present day, is necessarily a comprehensive one, and it is 

 sufficiently manifest that the most I can hope to compass within 

 the limits of a short paper, is to touch on some of the principal 

 features it presents. 



It will be well to first consider for a moment the present con- 

 dition of the earth, before we go back to the earlier stages of its 

 existence, and I will remind you that as at present constituted, it 

 has a specific gravity of 5 '4, and consists of 63 different kinds of 

 matter, which having hitherto proved undecomposable are conse- 

 quently termed simple bodies or elements. 



Some of these elements are gaseous, one or two liquid, but the 

 greater majority are solid : all, however, — and to this I would invite 

 your special attention, — even such heavy bodies as lead, iron, and 

 copper, under proper conditions can be easily made to assume a 

 gaseous form. 



It has lo)ig been conjectured that our earth did at one time in 

 reality exist in a gaseous or nebulous state, although it was little 

 thought that any proof, direct or indirect, could ever be obtained 

 in favour of such a theory. We have now, however, from our 

 knowledge of the composition of existing nebulae, strong evidence 

 in its favour. 



It has happened that many of those misty cloud-like bodies in 



