Alchemy Well

The Alchemy Well is an Alchemy Machine, left by the Neox, that features in Golden Sun: Dark Dawn. The Alchemy Well is located in the underground portion of Ayuthay. The Alchemy Well's encyclopedia entry reads as follows:
 * "This ancient machine was built by the Neox to create water in vast quantities. The machine can be put in reverse with the Arid Heat Psynergy from the Sand Prince Stone."

Mechanics
The Alchemy Well works off of the principles of Alchemy, by blending the elements of Earth and Wind to create Water. When functional, the Alchemy Well serves as a major source of water for Ayuthay, which would otherwise be inhospitable. When its power is combined with the corresponding Alchemy Forge of Passaj, the two provide water to all of Ei-Jei. The Alchemy Well apparently could be activated by a Mercury Adept, but only becomes fully functional once the Luna Mask is installed. The flow of the Alchemy Well can be reversed by using the Arid Heat Psynergy. To return from reverse flow to normal flow, a Mercury Adept must use Douse.

History
The Alchemy Well was created in ancient times, through the combined efforts of the Jenei, ancient Adepts, and the Exathi, a race of master craftsmen. Following the sealing of Alchemy, the Alchemy Well would go inactive. As there apparently existed no Jenei to allow the Well to remain functional, the surrounding region would slowly become inhospitable desert.

Approximately ten years after the Golden Sun event, a mysterious Mercury Adept would arrive in Ayuthay. The mysterious Adept would restart the Well using his Psynergy, then find an artifact known as the Luna Mask. The Luna Mask, when installed on the Alchemy Well, allowed the Ayuthay citizens, descendants of the Exathi, to control and profit from the Alchemy Well. After this, the Mercury Adept would stay just long enough to fall in love with Veriti, sister to Ayuthay's King Paithos, and conceive a child with her. The Mercury Adept would leave after the child's birth.

The child, Amiti, would be orphaned by the death of his mother, and raised by Paithos. 20 years after the Alchemy Well's restoration, Matthew's party of Adepts would enter Ayuthay, seeking a way into the Ouroboros, built by the ancient Ayuthay Exathi. In order to do so, the party would need the Insight Glass found in Barai Temple, hidden underwater. Amiti, a Mercury Adept himself, accompanies the Adepts, and explains the Alchemy Well's mechanics to them. Matthew's party set the Well into reverse by using the Arid Heat Psynergy. This allows them access to the temple, where they get the Glass. This eventually allows the Adepts to gain the Sol Mask, enabling an Alchemy Forge in Passaj to be activated. However, once activated (and the Well's reverse setting turned off) the Well truly starts to operate, showering much of Ei-Jei with water, converting the arid lands into lush, fertile plains. What the party does not know is that this machine acts to power the Apollo Lens, a devastatingly powerful weapon seen in the game's finale.