since meaning 2 is the essence of anything, and the potash (from pot ash-- you started with ashes from the fire place) is a in a very week solution, you then evaporate the water, to leave behind the potasium, (in the form of a salt.)
a whole industry of salt and chemical came from wood ashes- some of it evolved from indian practices of making a mild acid solutions, to treat corn to make hominy, and the common practice of burning to both clear the land, and enrich the soil.
Sodium bi-carbonate (baking soda ) is an other by product of distilling leach water.
Salt, (that is sodium cloride) was being extracted from brine in mining/chemical industries all over the north (and one place in Kentucky) Cape Cod,MA, Watkins Glenn, NY, Midland MI, were (and still are to some degree)industrial centers as a result of the brine opperations, there were many other places, to numerous to name.
after the sodium cloride was removed, other salts would also evaporate out.
at first, the brine left over after common salt was removed was considered waste, but later, it was refined further.
