50 HALF AN HOUR WITH SEAWEEDS. 



food, so do these seaweeds secrete that oxygen with- 

 out which the swarming myriads of marine life would 

 die of asphyxiation ; taking up, meantime, the car- 

 bonic acid, absorbing it into their tissues, and thus 

 turning it into the solid, nutritious, and in many 

 cases the only food obtainable by them. 



" Ever drifting, drifting, drifting, 



On the shifting 

 Currents of the restless main ; 

 Till in sheltered coves, and reaches 



Of sandy beaches, 

 All have found repose again." 



LONGFELLOW. 



