What does the word alchemy mean? (From Hawthorne's The Scarlet Letter)

Alchemy was an early form of chemistry with magical and philosophic associations, studied in the Middle Ages. Its aims were to change base metals into gold and to discover the secret of eternal life.

"My studies in alchemy," observed [Roger Chillingworth], "and my sojourn, for above a year past, among a people well versed in the kindly properties of simples, have made a better physician of me than many that claim the medical degree.

From Hawthorne's The Scarlet Letter.