Page:The American Cyclopædia (1879) Volume I.djvu/645

 AQUARIAN'S AQfAKir.M 009 AQUARIANS, or Hydroparastatae, a sect of jiscetics in the early Christian church who, from scruples against the use of wine, were in the habit of consecrating water for sacra- mental purposes. It was founded in the 2d century by Tatian, a disciple of Justin Martyr. AQUARIUM, or Aqnavi variant, a term applied to certain artificial arrangements for the exhibi- tion and study of living animals and plants in- habiting either fresh or salt water. To Mrs. Power, a lady of French descent, belongs the , credit of first adopting the aquarium as an aid to scientific research. This intelligent and en- , thusiastic naturalist, during the year 1832, be- gan the study of the fishes and algae off the I coast of Sicily, by transferring them to glass tanks in which the water was often renewed ; j and this renewal or revivification of the water was long regarded as essential to the health and vigorous growth of the inmates, it being argued that as the air is contaminated by the breathing of animals living upon the surface, and its oxygen is combined with the carbon furnished by the organic body, so the air con- i tained in the water is consumed by administer- | ing to animal life, and the gaseous product is not only unfit for longer sustaining this, but, unless removed, proves fatal to it. But subse- quent investigations into the various phenom- ena of vegetable and animal growth have de- termined that it is the office of plants to re- store to the atmosphere the oxygen, and ab- sorb the excess of carbon ; and it appears that the subaqueous vegetation fulfils the same office in preserving the purity of the air in the water, upon which depends the life of the ani- mals it contains; and that this balance may not be destroyed by the presence of poisonous gases, the results of decomposition and decay, it was found needful to add certain animals which feed on decomposing vegetable matter, and act as the scavengers in this community. Such are the various species of the molluscous ani- mals, as the snails. It is also of importance to guard against the preponderance of animal life in these artificial tanks or jars; for although there can hardly be too many plants for the health of the animals, as long as they grow healthily and do not decompose, yet an ex- cess of animals over plants will disturb the bal- ance, and lead to the destruction of the for- mer. Valisneria spiralis, various species of chara, anacharis alsinastrum, stratiotes aloides, callitriche autumnalis or vernalis, ranuncu- lus aquatilis, and myriophyllum spicatum are among the fresh-water plants adapted to this purpose. The fresh-water aquarium is more easily constructed and requires less skilful management than the marine tank. It should be square or hexagonal, as curved surfaces dis- ; tort the forms of the inmates, and a greater number of sides increases the liability to leak- age. Where metal corner posts are used, they should be plated if possible, as the oxidation of the metal often results disastrously. The glass plates should be held in position by hy- 40 VOL. i. 40 draulic cement ; that known as Scott's is highly recommended. Where putty only is available, it should be painted, the tank filled with water for a week or more, and then carefully cleaned before receiving the fishes and plants. The bottom should be covered to a depth of an inch or more with well washed river sand, and its surface thickly strewn with pebbles; clay or mould should be avoided, both because of the vegetable germs it may contain, and because its frequent disturbance by the fish renders the water turbid. The use of tastefully arranged rock work adds greatly to the beauty ; but rocks containing metallic substances should be re- jected ; and where shells are used, they should first be well soaked or calcined in order to destroy all organic matter contained in them. In constructing these arches or columns Port- land cement may be used to advantage, and some point of the structure should project above the water level. Thus arranged, the tank, which should be at least 12 inches deep, may be tilled with fresh spring or river water to within an inch of the top, and it is then ready for occupation. Such fresh-water plants as the butomus, nymphcea, and alisma should Fresh- Water Tank. have their fibrous roots extended and gently imbedded in the sand, with a layer of pebbles to keep them in position. All river plants that bud and root from points on the stem, as ana- charis, ranunculus, callitriche, and chara, can be raised by securing them in tufts to the sandy bottom by a light layer of pebbles. There are certain plants which, in addition to beauty of structure and vigorous growth, are of great service as oxygen producers ; such are the - lisneria spiralis, water thyme (anacharis al- sinastrum), with the flowering water crowfoot (ranunculus aquatilis), milfoil, and starwort. Though the stocking of the aquarium depends largely upon the purpose it is to serve, yet cau- tion is needed as to the number and habits of the inmates. A young pickerel only an inch and a half long has been known to devour 25 minnows in a week. For general interest, the stickleback takes the lead among the fishes, and for beauty the gold fish, tench, gudgeon, perch, minnow, and Prussian carp all flourish, with snails and mussels as purifiers. Where the proper balance is not easily maintained