Alchemical Symbolism in the VMS

[Barbrey]

If by "alchemical salt" you mean a Salt that is a principle and not a salt, like Sulphur is not sulphur and Mercury is not mercury, no.

I added the word "alchemical" to distinguish it, precisely, from common salt. Perhaps this "salt" existed under another name?

Hmm, it would help if you gave the context - where did you read about alchemical salt?  Because as a principle it means a number of things and can even stand in for processes, such as contraction or crystallization. It was sometimes substituted for the element of “earth” itself. But I think, if I remember correctly, you might be referring to the “salt of Mercury”, which is the form Mercury took before being forced into the chemical marriage with the “oil of Sulphur”. I’ll have to check that.