The Philosopher and his Flask vs The Stranger and Free Spirit
"The mercurial spirit - in both its Feminine and Masculine forms - is aware of the alchemist as he begins his opus.The alchemist’s insistence on keeping the alembic closed (and its content therefore private) encourages the patient to use the material in an appropriately introverted way and avoid betraying the integrity of the process either by recklessly acting it out or by fruitless theorizing."
The Philosopher on his journey investigating the Elements of nature is both like The Stranger who's apart from the group for a while and The Free Spirit who follows his intuition and imagination in pursuit of other horizons. The heron's house is closed, like the Philosopher's alembic, symbolizing a solitary introspection. He stays by the pine tree, which represents wisdom and longevity. On the other side, the two horses in the Free Spirit wear the same colors as the Philosopher, red and blue, which represents the mercurial spirit, both in its feminine and masculine forms.
Note: the quote is from the book by J.L. Henderson and D.N. Sherwood, Transformation of the Psyche: The Symbolic Alchemy of the Splendor Solis