Electricity is the flow of electrons, who move from negative to positive, the opposite of what you would normally expect.
Maybe I’m biased because I’m a welder, but it always made more sense to me that electricity flows from the negative. Like , if the positive moved, wouldn’t you change the element of the wire after a while? It also helps that you can tell the difference if an arc is positive or negative relative to the stinger depending on how the metal reacts, at least to a welder. I know that doesn’t make any sense at all but it does to another welder lol
So, when Ben Franklin named them, it was in terms of something like “excess of electricity”. A positive excess of charge, like in the glass he used to define the term, is actually a deficit (negative excess) of electrons, which are the real fluid.
Later on Crooks (I think?) figured out that if he cleared all the air out of a tube with mercury, he could force electrons out of the metal into open space, at the negative cathode end, and at that point they realised it was backwards.
