xliv PKOCEEDINGS OP THE GEOLOGICAL SOCIETY. 



the seasons, of the trade winds, of the Gulf-stream are as much the 

 results of the reaction between these inner activities and outward 

 forces, as are the budding of the leaves in spring and their falling 

 in autumn the effects of the interaction between the organization of 

 a plant and the solar light and heat. And, as the study of the acti- 

 vities of the living being is called its physiology, so are these pheno- 

 mena the subject-matter of an analogous telluric physiology, to which 

 we sometimes give the name of meteorology, sometimes that of phy- 

 sical geography, sometimes that of geology. Again, the earth has a 

 place in space and in time, and relations to other bodies in both 

 these respects, which constitute its distribution. This subject is 

 usually left to the astronomer ; but a knowledge of its broad outlines 

 seems to me to be an essential constituent of the stock of geological 

 ideas. 



All that can be ascertained concerning the structure, succession of 

 conditions, actions, and position in space, of the earth is the matter 

 of fact of its natural history. But, as in biology, there remains the 

 matter of reasoning from these facts to their causes, which is just as 

 much science as the other, and indeed more ; and this constitutes 

 geological setiology. 



Having regard to this general scheme of geological knowledge and 

 thought, it is obvious that geological speculation may be, so to 

 speak, anatomical and developmental speculation, so far as it relates 

 to points of stratigraphieal arrangement which are out of reach of 

 direct observation ; or it may be physiological speculation, so far as 

 it relates to undetermined problems relative to the activities of the 

 earth ; or it may be distributional speculation, if it deals with modi- 

 fications of the earth's place in space ; or, finally, it will be setiological 

 speculation, if it attempts to deduce the history of the world, as a 

 whole, from the known properties of the matter of the earth in the 

 conditions in which the earth has been placed. 



For the purposes of the present discourse I may take this last to 

 be what is meant by ' geological speculation.' 



Now uniformitarianism, as we have seen, tends to ignore geolo- 

 gical speculation in this sense altogether. The one point the catas- 

 trophists and the uniformitarians agreed upon when this Society 

 was founded, was to ignore it. And you will find, if you look back 

 into our records, that our revered fathers in geology plumed themselves 

 a good deal upon the practical sense and wisdom of this proceeding. 

 As a temporary measure, I do not presume to challenge its wisdom ; 

 but in all organized bodies temporary changes are apt to produce 

 permanent effects ; and as time has slipped by, altering all the con- 

 ditions which may have made such mortification of the scientific flesh 

 desirable, I think the effect of the stream of cold water which has 

 steadily flowed over geological speculation within these walls, has 

 been of doubtful beneficence. 



The sort of geological speculation to which I am now referring 

 (geological aetiology, in short) was created as a science by that famous 

 philosopher Immanuel Kant, when, in 1755, he wrote his * General 

 J^atural History and Theory of the Celestial Bodies ; or an attempt 



