less known tenants of the sea. They are best described as the River and
the Marine Aquarium, and they differ somewhat from each other. We shall
speak first of the fresh-water aquarium.

The tank being prepared, and well-seasoned, by being kept several weeks
alternately full and empty, and exposed to the sun and air, so that all
paint, oil, varnish, tannin, etc., may be wholly removed, the next thing
is to arrange the bottom and to plant it. Some rough fragments of rock,
free from iron or other metals that stain the water, may be built into
an arch with cement, or piled up in any shape to suit the fancy. The
bottom should be composed entirely of shingle or small pebbles, well
washed. Common silver sand, washed until the water can be poured through
it quite clear, is also suitable.

Mould, or soil adapted to ordinary vegetation, is not necessary to
the aquatic plants, and is, moreover, worse than useless; since it
necessitates the frequent changing of the water for some time, in order
to get rid of the soluble vegetable matter, and promotes the growth of
Confervae, and other low forms of vegetation, which are obnoxious.

Aquatic plants of all kinds have been found to root freely and flourish
in pebbles alone, if their roots be covered. The plants should be
carefully cleared of all dead parts; the roots attached to a small
stone, or laid on the bottom and covered with a layer of pebbles and
sand.

The bottom being planted, the water may be introduced through a
watering-pot, or poured against the side of the tank, so as to avoid any
violent agitation of the bottom. The water should be pure and bright.
River-water is best; spring-water will do, but must be softened by the