OF NATURAL PHILOSOPHY. 287 



shall only find ourselves bewildered in a mass of 

 conflicting, because imperfect, evidence. It is ob- 

 vious that the only way to decide the point is to as- 

 certain, by very precise and careful observations at 

 proper stations on coasts, selected at points where 

 there exist natural marks not liable to change in 

 the course of at least a century, the true elevation 

 of such marks above the mean level of the sea, and 

 to multiply these stations sufficiently over the whole 

 globe to be capable of affording real available know- 

 ledge. Now, this is not a very easy operation (con- 

 sidering the accuracy required) ; for the mean level 

 of the sea can be determined by no single observ- 

 ation, any more than the mean height of the baro- 

 meter at a given station, being affected both by 

 periodical and accidental fluctuations due to tides, 

 winds, waves, and currents. Yet if an instrument 

 adapted for the purpose were constructed, and ren- 

 dered easily attainable, and rules for its use care- 

 fully drawn up, there is little doubt we should soon 

 (by the industry of observers scattered over the 

 world) be in possession of a most valuable mass of 

 information, which could not fail to afford a point of 

 departure for the next generation, and furnish 

 ground for the only kind of argument which ever 

 can be conclusive on such subjects. 



(323.) Geology, in the magnitude and sublimity 

 of the objects of which it treats, undoubtedly ranks, 

 in the scale of the sciences, next to astronomy ; 

 like astronomy, too, its progress depends on the 

 continual accumulation of observations carried on 

 for ages. But, unlike astronomy, the observations 

 on which it depends, when the whole extent of the 



