FRESH-WATER AQUARIA. 
L. MURBACH. 
Tue lover of nature, taking his early spring walks, often 
feels the desire to cultivate a nearer acquaintance with the 
living things that he sees in ponds and pools along his way. 
He may dip up samples here and there, taking some water 
weed and a string of the jelly beads containing toads' eggs, 
place them in glass jars or aquaria at home, and gain further 
pleasure, for a few days at most, and then the whole mass 
becomes foul and is thrown away. His ill-success is due to 
the improper balance between animals and to the popular 
mi tion that an aquarium with animal life should be 
uncovered so that the animals can get air to breathe; and the 
remedy lies in keeping the aquarium, once properly balanced 
from one spring to another, so well covered that scarcely any 
evaporation of water can take place. To this then may be 
added new organisms from time tó time. 
None of the numerous notices on the keeping of aquaria 
that I have seen describe permanent aquaria without changing 
the water; yet this is one of the most desirable features — to 
keep the aquarium, year in year out, for observing the interest- 
ing succession of forms, often including representatives of ani- 
mal groups from Protozoa to Crustacea, with an almost equal 
diversity of aquatic plants. 
Some of the pond scum (alge), drawn by light and ad- 
hering to the side of the glass, may be made to decorate the 
side of the aquarium with almost any pattern in green — let- 
ters, or your monogram if you choose. Some of my experience 
may be useful to the reader, and I gladly give it for what it 
mày be worth. 
Seeing the algæ in my largest aquarium accumulate on the 
side most strongly lighted, it occurred to me that they might 
be made to form a definite design by regulating the light. 
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