16 



DROPS OF WATER. 



fluids found in animals and vegetables, strong 

 acids, and also the briny ocean, are full of these in- 

 teresting creatures. One kind of phosphorescence, 

 (an appearance which is so often observed by 

 the sea-side and at sea,) is occasioned by some 

 species ; and when we remember that this lumi- 

 nosity often extends for miles, we are lost in 

 astonishment at the immensity of their numbers. 

 And here I may mention the evident use of 

 these wonderful beings. They appear wherever 

 decaying animal or vegetable substances are 

 found in water, and are extremely useful in de- 

 stroying what would otherwise taint the air with 

 noxious gases and smells. Minute algae also 

 assist in preserving the purity of the water in 

 which they live ; they serve as food, also, to 



