STUDY IV. 167 



food and fhelter for their young. And for the 

 preCervation of thefe adaptations it is, that Nature 

 has fortified every (bore with long banks of fand, 

 flielves, enormous rocks, and iflands, which are 

 arranged round them, at proper diftances, to pro- 

 tea; them from the fury of the Ocean. 



She has employed fimilar difpofitions in forming 

 the beds of rivers, as we fhall (liew in the fequel 

 of this Study, though we have room only to glance 

 at a fubjeâ; fo new, and fo fertile in obfervation. 

 Accordingly, (he has made the current of rivers to 

 flow, not in a ftraight line, as they muft have run, 

 had the laws of Hydraulics been obferved, becaufe 

 of the tendency of their motions toward a fingle 

 point ; but Ibe makes them wind about for a long 

 time through the bofom of the Land, before they 

 pour themfelves into the Sea. 



In order to regulate the courfe of thefe rivers, 

 and to accelerate or retard it, conformably to the 

 level of the countries through which they flow, ihc 

 pours into them lateral rivers, which accelerate 

 it in a flat country, when they form an acute angle 

 with the fource of the main river; or which retard 

 it in a mountainous country, by forming a right, 

 and fometimes an obtufe, angle, with the fource 

 of the principal flream. Thefe laws are fo infal- 

 lible, that a judgment may be formed, fimply from 



M 4 the 



