How could an underwater civilization develop electricity?

Question

Electricity pervades our daily lives, and makes possible a lot of technological achievements. Harnessing it helps the development of any civilization. The thing is, water - especially sea water - is a great conductor of electricity.

I'd like to add electricity to an underwater civilization I'm working on, but I have two problems to deal with.

1. How would the civilization discover electricity?
2. How could the civilization use electricity (without electrocuting themselves)?

Some details about the civilization:

• They are octopus-like, insofar as they have tentacles for manipulation of objects.
• They have gills.
• They don't have fire - although I'll possibly address that in a future question. They might. I'm addressing this in How could an underwater civilization develop fire?.
• The technological level is somewhere around that of the 1700s in Europe, if that helps.

Answer 1

1. They could easily discover electricity in electric rays or similar sea creatures. They could discover the “batteries” of the rays; in fact, there is a possibility that the corresponding human research on rays in the 18th century brought Galvani and Volta to further investigate electricity, so it should be feasible for your civilisation as well. As for electric safety concerns, the discharging of electrocytes in rays uses some particular chemical which closes the circuit, so your creatures could possibly figure out by trial and error how to discharge the rays without short-circuiting them (after all, the electric rays themselves do exactly that).

2. Clearly, after understanding how electrical rays work, they could use this technology for hunting or battle. On the other hand, it would obviously be difficult for them to create electric circuits. One very human-like way to make some progress I can think of is to figure out that an artificially created air bubble (just by using some vessel first brought out of the water and then submerging it like a diving bell) is much safer in terms of absence of short-circuits and then starting to make experiments only under a diving bell (reaching the objects from outside using tentacles); I guess, a 18th century-like tech level presumes they know what air is and how to keep some volumes of it under water. After that discovery, they could basically proceed with a 19th century human-like experiments on electricity using the “batteries” from ocean creatures to build huge battery stacks, if they don't discover a better way to build them.

Answer 2

How would the civilization discover electricity?

That one is easy: There are animals in the sea that use electricity, like the electric eel. The underwater civilization would certainly be curious about how that works.

How could the civilization use electricity (without electrocuting themselves)?

The first use of electricity will probably be as weapon — after all, that's the use they know about from the animals. Initially they probably would use captured electric eels. Assuming they know metals, they probably will find out that metals can be used to protect from electric eels (Faraday cage!). They will probably also find out that there are materials which shield you from electricity, like stone (note that since the complete water around them is conducting, it suffices to keep the distance the electricity has to travel to reach you large enough). As people learn more, they'll probably find how to make it yourself (using electrochemical processes) and that they can be used to create metals from water (by electrolysis of the salts). It will probably be quite some time until they manage to properly insulate it, so that it can be transported to specific places, and be used without too much danger.

However it will probably never become a common household item, as you cannot have a simple plug (meaning uninsulated electricity being exposed), and any defect in the insulation means huge danger. So it will probably be used only in a professional setting and by the military.

Answer 3

How about a biological interpretation of electricity? What is electricity? It's electrons moving through a conductive medium, like an ionized gas or a metal. Essentially, it's signals flowing through a medium. What signals could be used to replace this underwater? Water flows are too slow and inaccurate. Sound is faster, but would be just as big a nuisance as electricity for aquatic creatures.

However, there is a signal similar to electricity that could be used for this: biological nerves. Nerves actually use electricity, but a low-energy, isolated version of it. An aquatic race might develop a bionetwork of nerves to transmit their electricity. They could develop biological batteries and power generators (basically specially bred fish derived from electric fish from your world). I mean, Earth has around 300 species of electric fish, so it's not a stretch to assume that your world might have a few itself.