Guest essay by Charles Battig, MD | The alchemists of old were diligently ambitious in their goals. These antecedents of modern chemistry were not hindered by a lack of knowledge of atomic structure and physical chemistry when it came to setting priorities. Lacking a nuclear reactor and knowledge of atomic reactions, they postulated the existence of “The Philosopher’s Stone.” This mythical substance was thought to be able to turn base metals into gold, and endow eternal life and wisdom to its discoverer.

Another magical substance hypothesized was the “universal solvent.” Such a substance would be able to dissolve all other substances, including gold. Philosophical discussions over what container could hold this universal solvent must have been lively. Aqua regia, a mixture of concentrated nitric and hydrochloric acids, was eventually discovered, and comes close to the definition. This “royal water,” named by the alchemists because of its ability to dissolve gold…