194i HISTORY OF 



was at first effected ; so that it entirely got ria of its inundations, 

 or only demanded a slight assistance from man for that purpose." 

 This may be the origin of all bogs, which are formed by the 

 putrefaction of vegetable substances, mixed with the mud and 

 slime deposited by waters, and at length acquiring a sufficient 

 consistency. 



From this we see what powerful eife(;ts the sea is capable of 

 producing upon its shores, either by overflowing some, or desert- 

 ing others; by altering the direction of these, and rendering 

 those craggy and precipitate, which before were shelving. But 

 the influence it has upon these, is nothing to that which it has 

 upon that great body of earth which forms its bottom. It is at 

 the bottom of the sea that the greatest wonders are performed, 

 and the most rapid changes are produced ; it is there that the 

 motion of the tides and the currents have their whole force, and 

 agitate the substances of which their bed is composed. But all 

 these are almost wholly hid from human curiosity : the miracles 

 of the deep are performed in secret ; and we have but little in- 

 formation from its abysses, except what we receive by inspection 

 at very shallow depths, or by the plummet, or from divers, who 

 are known to descend from twenty to thirty fathoms.' 



The eye can reach but a very short way into the depths of the 

 sea ; and that only when its surface is glassy and serene. In 

 many seas it perceives nothing but a bright sandy plain at bot- 

 tom, extending for several hundred miles, without an interven. 

 ing object. But in others, particularly in the Red Sea, it is 

 very different : the whole bottom of this extensive bed of waters 

 is, literally speaking, a forest of submarine plants and corals, 

 formed by insects for their habitation, sometimes branching out 

 to a great extent. Here are seen the madrepores, the sponges, 

 mosses, sea^mushrooms, and other marine productions, covering 

 every part of the bottom ; so that some have even supposed the 

 sea to have taken its name from the colour of its plants below. 

 However, these plants are by no means peculiar to this sea, as 

 they are found in great quantities in the Persian Gulf, along 

 the coast of Africa, and those of Provence and Catalonia. 



The bottom of many parts of the sea, near America, presents 

 9 very different, though a very beautiful, appearance. This is 



1 Phi]. Trans, vol. iv. part. ii. p. 192. 



