212 



HABIT AKD INTELLIGENCE. 



[chap. 



Oceano- 

 graphy. 



Geo- 

 graphy. 



Geology. 



Mineral- 

 ogy- 



graphy/ or the science which treats of the tides, the cur- 

 rents, and other phenomena of the ocean ; — except the tides, 

 these almost exclusively depend on the winds and on tem- 

 peratures, so that oceanography can scarcely be separated 

 from the theory of climate.^ Next in the order of vastness 

 and simplicity come the sciences of those phenomena 

 which are less extensive than the entire siu-face of a planet : 

 these are geography, or the determination of the outlines 

 of coasts, the courses of rivers, and the heights of moun- 

 tains ; and physical geology, or the science which treats of 

 the constitution of the crust of the earth, and the causes 

 to which that constitution is due. The facts of geology, as 

 I have already remarked, cannot be referred to any single 

 set of laws. Next in the order of the magnitude and 

 generality of the phenomena comes mineralogy, or the 

 science of the molecular structure and chemical composi- 

 tion of the rocks : it is, in fact, the molecular, chemical, 

 and crystallographic branch of geology, and is related to 

 physical geology much in the same way that molecular 

 and chemical physics are related to general dynamics. 

 And last of all, for the special and limited character of 

 its phenomena, is palasontology, with the laws of the dis- 

 tribution of living species : the facts of this science in 

 a great degree depend on those of biology, though, as I 

 have shown in the chapter on Distribution,^ this depen- 

 dence is much less rigid than might have been expected. 



There is thus a kind of rough approximate parallelism 

 between the two series of sciences, the abstract and the 

 cosmic. Of course there is no cosmic science in any 

 sijondences Way Corresponding to logic and mathematics. But astro- 

 between nomy pretty accurately corresponds to dynamics ; terres- 

 series. trial magnetism corresponds with perfect accuracy to the 



1 Or what Maury calls the "physical geography of the sea." The 

 absui'dity of the expression "grcography of the sea" may be best shown 

 by translating it into German, in which language it would be " Erd- 

 beschreibung des Meeres." 



- The general theory of the tides belongs to astronomy, but those more 

 special tidal phenomena which cannot be deduced from the general theory, 

 but must be ascertained by observation, cannot be called astronomical. 



3 Chapter XVIll. 



Palaeon- 

 tology, 

 and the 

 distribu- 

 tion of 

 species. 



Corre- 



