Aquarium
2 of the 6 encyclopedias on this shelf carry an entry for Aquarium. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a tank of water for live plants and animals. An aquarium is not expensive nor hard to keep up. It may be a large glass receptacle or a wooden box with glass ends. Put in an inch of sand, a few stones for shelter, some snails, some water drawn with a dipping tube from a weedy pond bottom for tiny animals, a minnow or two, and a tadpole. Root some water plants in the sand to purify the water, and let a chip float on the surface. Keep it in the light, but not in the sun, and you have an aquarium to experiment with. Country schoolteachers sometimes convert a washtub into an aquarium with great success. Some high schools and nearly all colleges and universities possess aquaria in connection with their botany and zoology departments. Entire rooms, or even an entire building, may be used in connection with natural history museums or biological stations. One of the largest and most beautiful salt-water aquaria in the world is at Naples, Italy. It occupies the ground floor of a building more than 100 feet long. Glass tanks, reaching from the floor to the ceiling, are built into the walls. Salt water is being forced constantly into these tanks from the sea. Each tank is numbered, only animals representing a certain marine type are placed in each; e. g., in one, only spiny skinned animals are seen; in another worms only; in still another bony fishes only. Each tank is designed to furnish the conditions or environment to which the animals are accustomed in their free state in the sea. Therefore one sees grottoes, rocks, variously colored sand, sticks of wood, debris, green, red, and brown plants, empty shells, etc., as the furniture of the tanks. Some of the animals are themselves very highly colored, red, green, yellow, blue; some are all of one color; others are spotted, striped, or speckled. The observer sees them moving about him in much the same way as if he had himself been lowered into the sea, and the plants and animals left in their accustomed places.
Collier's New Encyclopedia (1921)
an artificial tank, pond, or vessel, filled with salt or fresh water, and used, in the former case chiefly for the purpose of keeping alive marine animals in circumstances which render it easy to study their habits, and in the latter for cultivating aquatic plants.
What Has Changed in the Last Century
Aiton's 1910 description of Naples as "one of the largest and most beautiful salt-water aquaria in the world" — floor-to-ceiling glass tanks in a hall 100 feet long — still stands as a description of that building, which survives as the oldest working public aquarium in Europe. But the scale has been transformed by acrylic panels, which can be moulded thick and curved in a way plate glass never could: the Georgia Aquarium, opened in 2005, holds roughly 24 million litres and keeps whale sharks, while Monterey Bay (1984) pumps seawater straight from the bay much as Naples did. The washtub end of the hobby has changed too, with electric filters, heaters and LED lighting letting home aquarists keep living corals and captive-bred marine fish that no 1910 school could have sustained. What Aiton and Collier's do not anticipate is the ethical argument now attached to the whole enterprise, especially over captive whales and dolphins.
Written for this edition, 2026.