AQUAIUOM. 



realm of its own plants. Tlie plants, besides furnishing nutii- 

 tipus pasturage, carry on a wholesonie chemical process, under 

 the surface of the water, for the manufacture of a main ingre- 

 dient in the breath of life. The fishes, however, are not left 

 to depend whoUy on this means of support. The bfllows of 

 the great ocean beat the air, and, catching it in the form of 

 foam bubbles, force it down to considerable depths, and cause 

 it, both in its descent and in its rising again to the surface, to 

 come into contact with the water that requires its purifying 

 influence. The sea beats upon the beaches and dashes itself 

 into a thick froth upon the rocks ; that is to say, beats air into 

 itself on an extensive scale, and carries the precious bubbles so 

 obtained even to considerable depths. Its movement causes a 

 constant change of surface water, to say nothing of the influence 

 of currents." This may be worth the consideration of unthink- 

 ing rhymsters who have no ambition beyond a jingle, and who 

 hsp prettily about the waves " beating idly on the shore." If 

 such a stupendous business as supplying millions of swimming 

 and creeping creatures with the first principle of life, is idle- 

 ness, pray what is the correct term for spoiling fair paper with 

 such vapid sorawlings, of which the above-quoted line is a 

 sample P 



To return, however, to our tank. Owing to the more slug- 

 gish life of marine organization, and the greater amount of 

 disorganized matter evolved, it is more difficult to preserve the 

 balance of health in the salt than the fresh water aquarium. 

 Contamination must be guarded against with the most scru- 

 pulous care. Sometimes, although every fish and every spray 

 of sea-weed may appear perfectly healthy, the water will be- 

 come as opaque as though a glass of milk had been added to 

 it, and your nose will insist that animal decomposition is the 

 cause of it. In all probability that sagacious organ is right, — 

 certain members of a family of minute creatures imperceptibly 

 attached to your ornamental rock-work have given up the 

 ghost ; and unless yon speedily empty your amateur ocean, and 

 provide your pets with a new sea, they will speedily die too. 



After all, however, the difficulties of keeping the marine tank 

 in a healthful condition are not nearly so great as they seem. 

 Thorough aeration is all that is required ; and to secure this it 

 is only necessary to take every morning a portion of water out 

 of the aquarium, and to allow it to drip back from some little 

 height into the vessel. The water thus exposed to contact 

 with the air, drop by drop, and further entangling and carry- 



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