From the Molecular World:A Nineteenth-Century Science Fantasy

Picture this: You and a friend are visiting a newly constructed aquarium. You both walk through it, looking at the huge, gleaming compartments, each meticulously labelled. But here's the thing: there are no animals in this aquarium. The first compartment that you look at is labelled - 'Hydrogen'. Peering inside through the glass body of the compartment, you see a 'scramble of incredibly tiny bodies swarming around in pairs'.