Page:The American Boy's Handy Book edition 1.djvu/88
and cause little bubbles of oxygen to collect and rise from the vegetation. A window facing the north or northeast is the best situation. When you observe that the plants are in a thriving condition, and that a new vegetation has apparently sprung spontaneously into existence, carpeting the rockery and sides of the glass with green, then and not until then introduce the animals. Be very careful not to overstock the tank. Remember, no matter how bright and pleasant a room may be with one or two persons in it, the atmosphere of that same room will become foul and heavy in the presence of a large crowd, and if the ventilation be insufficient, headache, dizziness, and death will ensue, as was the case in the terrible Black Hole of Calcutta. Unless you want to make a miniature "black hole" of your aquarium, do not overcrowd it. Let the water have light, but no sunshine. Put a glass cover over the tank to keep out the dust, but let the cover fit loosely enough to allow a free circulation of air. The glass top-piece will in a measure prevent evaporation. If, however, any water is lost from this cause, recollect that the salts contained in sea water do not evaporate, and consequently the tank may be replenished with fresh water equalling the amount evaporated. Beware of the hot summer months. I have always found it more difficult to keep the water pure during July and August than any other part of the year. Do not allow smoking in the room where your aquarium is, as the foul atmosphere taints the water. I once lost almost all the inhabitants of a thriving marine tank, by allowing a party of gentlemen to smoke in the room where it was standing. If you have company in the evening, the room, as a rule, will become overheated, and you should take the precaution to wrap the sides of the tank with wet towels.
The prepared food mentioned in the preceding chapter will answer for some salt-water animals. Lean beef, cut in very small bits, may be dried and kept for feeding marine pets when oysters