Our functional conception of matter, developed earlier (Chapter XI), allows us to recognize in these two substances representatives of the Salt-Sulphur polarity. Indeed, glass as a mineral substance, which actually owes its specific character to the presence of silicon in it, clearly stands on the phosphoric-crystalline side, while resin, being itself a sort of 'gum', on the sulphurous-volcanic side. In fact, sulphur itself was soon found to be a particularly suitable substance for producing 'resin'-electricity.