IV. 



THE CHEMISTRY OF THE PRIMEVAL 

 EARTH. 



(1867.) 



The following paper is an abstract of a Friday-evening lecture, given before the 

 Royal Institution of Great Britain, London, May 31, 1867, and here reprinted from the 

 Proceedings of the Institution. As an attempt to bring together in a connected form 

 some of the latest conclusions of chemical and geological science, it attracted at the 

 time considerable attention, having been frequently reprinted, several times translated, 

 and adversely criticised both in the Chemical News and the Geological Magazine. My 

 replies to these criticisms the reader will find in these same journals for February, 1868. 



As bearing upon the subject of the lecture, an Appendix is subjoined including a note 

 on the relation of the atmosphere of early times to climate, and to the temperature 

 near the sea-level. For further discussion upon the origin and mode of formation of 

 dolomites and gypsum, and their relation to the composition of the atmosphere, the 

 reader is referred to Paper VIII. in this volume. 



THE natural history of our planet, to which we give the name 

 of geology, is necessarily a very complex science, including, as 

 it does, the concrete sciences of mineralogy, botany, and zoology, 

 and the abstract sciences, chemistry and physics. These latter 

 sustain a necessary and very important relation to the whole 

 process of development of our earth from its earliest ages, and 

 we find that the same chemical laws which have presided over 

 its changes apply also to those of extra-terrestrial matter. Re- 

 cent investigations show the presence in the sun, and even in 

 the fixed stars, suns of other systems, the same chemical 

 elements as in our own planet. The spectroscope, that marvel- 

 lous instrument, has, in the hands of modern investigators, 

 thrown new light upon the composition of the farthest bodies 

 of the universe, and has made clear many points which the 

 telescope was impotent to resolve. The results of extra-terres- 

 trial spectroscopic research have lately been set forth in an 

 admirable manner by one of its most successful students, Mr. 



