Fusion is the principle of Hydrogen Bomb, where Fission is the principle of the Atomic Bomb.
Aurobindo, Adventure of Consciousness, Sat Prem wrote
If the Rishies had not known the secret behind all nuclear and solar fusions, they wouldnt have dared to speak about Supramental Transformation !
Alchemy was thought to be impractical, as nobody had ever transmuted baser metals into gold. Paracelsus, the Guru of Goethe, was an alchemist. SO was Nicholas Flammel, who wrote about the Serpent of India ( Kundalini ).
Baser metals represent our base, animal. Gold implies the true Gold in us , the Self, the Atman.
Yogic or Divine Alchemy is the ultimate formula of Wisdom It is the Descent of Orpheus in the Western and the Brahma Sakshatkaram or Atma Sakshatkaram or Nirvana or Samadhi of the Eastern !