490 THE CHEMISTRY OF CREATION. 



Calling to memory the wonderful facts elicited 

 upon the chemistry of the sunbeam, and its 

 connexion with vegetation, the inquiry naturally 

 arises, whether the vegetation of the deep is 

 also dependent with that of the land upon the 

 various energies of the solar ray? There exists 

 every reason to believe it is so dependent. 

 Direct experiments of a trustworthy character 

 and sufficiently numerous are yet wanting. But 

 it is found that vegetation generally ceases 

 at such depths as mark the extinction of the 

 solar ray. The light received by these plants 

 is of a greatly diminished intensity. Many of 

 them must live in little better than an alter- 

 nation of twilight and night. Even those 

 which occupy the littoral region must enjoy 

 much less of the power of the sun's ray than 

 the humblest plant dangling' on the rock in 

 mid-air. The actinic and the luminous rays of 

 light are those which appear chiefly to influence 

 the marine vegetation. In what way, it remains 

 for us to learn. Enfeebled though the solar 

 influences may be by their passage through the 

 water, they suffice to quicken the plant and to 

 enable it to sustain an active existence. We 

 are apt to imagine that sea-weeds are very slow 

 in growth, but this is in the case of many of 

 them an error ; a few months sufficing to cover 

 rocks with plants which had before been per- 



