From ''A Brief History Of Chemistry'' by Isaac Asimov: ''It seemed to Jabir that the different metals were made up of different mixtures of mercury and sulfur, and it remained only to find some material that would facilitate the mixture of mercury and sulfur in the proper proportions to produce gold.'' What I don't understand is if Jabir thought the ''different metals were made up of different mixtures of mercury and sufur'', why would production of gold need another material? Wouldn't just mixing MERCURY and sulfur in different proportions would do the job? Wouldn't addition of a different material actually make it something not gold? PS: I know that alchemy is not real, and no gold can be produced in such way.