Re: Can you tell me who brought up the theory of electrolytes?

Arrhenius first realized that certain substances split up into charged 
atoms called ions and that this occurred regardless of whether electricity 
passed through the solution. Debye just extended Arrhenius' theory by 
proving that the breakup of crystals into ions was complete when a crystal 
was dissolved.

How did Arrhenius figure out his theory?
This is a direct quote from the Arrhenius article in Britannica:

Well, he did so mainly from electrical-conductivity measurements and from 
molecular-weight studies (freezing-point depression, boiling-point 
elevation, and osmotic pressure). These studies showed that the number of 
solute particles was larger than it would be if no dissociation occurred. 
For example, a 0.001 molal solution of a univalent-univalent electrolyte 
(one in which each ion has a valence, or charge, of 1, and, when dissociated, 
two ions are produced) such as sodium chloride, Na+Cl-, exhibits colligative 
properties corresponding to a nonelectrolyte solution whose molality is 
0.002; the colligative properties of a 0.001 molal solution of a univalent-
divalent electrolyte (yielding three ions) such as magnesium bromide, 
Mg2+Br2-, correspond to those of a nonelectrolyte solution with a molality 
of 0.003. At somewhat higher concentrations the experimental data showed 
some inconsistencies with Arrhenius' dissociation theory, and initially 
these were ascribed to incomplete, or partial, dissociation. In the years 
1920-30, however, it was shown that these inconsistencies could be 
explained by electrostatic interactions (Coulomb forces) of the ions in 
solution. The current view of electrolyte solutions is that, in water at 
normal temperatures, the salts of strong acids and strong bases are 
completely dissociated into ions at all concentrations up to the 
solubility limit. At high concentrations Coulombic interactions may cause 
the formation of ion pairs, which implies that the ions are not dispersed 
uniformly in the solution but have a tendency to form two-ion aggregates 
in which a positive ion seeks the close proximity of a negative ion and 
vice versa. While the theory of dilute electrolyte solutions is well 
advanced, no adequate theory exists for concentrated electrolyte solutions 
primarily because of the long-range Coulomb forces that dominate in ionic 
solutions.