Alembic, crucible, all were there;
Their theories concerning the concept of matter and the origins of life were based upon a framework of false religious and philosophical assumptions. Once real science started to evolve the theories of the Alchemists were revealed for what they really were, totally unworkable, superstitious nonsense. None of them ever found the Philosopher’s Stone, but on a more positive note, as a result of their empirical experiments some did occasionally make important discoveries. However, those who did tended to be those who were more practical in their approach. Paracelcus, the discoverer of ether, was one. Although an Alchemist, he was also a brilliant theorist who refused to blindly accept the traditional methods, and introduced empirical testing: this format, the basis of scientific chemistry, sounded the death knell of Alchemy.
Of the others, all that can be said is that they wasted their entire lives searching for something that existed only in their fertile imaginations.