Although scientists never could quite turn lead into gold, they did attempt some noteworthy experiments

Alchemy May Not Have Been the Pseudoscience We All Thought It WasBy Richard Conniff, Smithsonian Magazine - February 2014

Throughout much of the 20th century, the academic community had little patience with alchemists and their vain efforts to transmute base metals into gold. Any contemporary scholar who even dared to write about alchemy, historian Herbert Butterfield warned, would "become tinctured with the kind of lunacy they set out to describe."

But, in the 1980s, some revisionist scholars began arguing that alchemists actually made significant contributions to the development of science. Historians of science began deciphering alchemical texts—which wasn't easy. The alchemists, obsessed with secrecy, deliberately described their experiments in metaphorical terms laden with obscure references to mythology and history. For instance, text that describes a "cold dragon" who "creeps in and out of the caves" was code for saltpeter (potassium nitrate)—a crystalline substance found on cave walls that tastes cool on the tongue.

Read the full article here: Alchemy May Not Have Been the Pseudoscience We All Thought It Was