"Let the manes put off their terror, let them put off their aqueous bodies with fire. Let them draw together the bones of the metal. Selvaggia, Guiscarda, Mandetta, Rain flakes of gold on the water Azure and flaking silver of water, Pallor of silver, pale lustre of Latona, By these, from the malevolvence of the dew Guat this alembic. Elain, Tireis, Allodeta Quiet this metal." - Ezra Pound
The Alchemist sells phials of most types of liquid (including cloning droughts and neutron flux!).
The Alchemist does not appear to replenish his stock.
The Alchemist can be found on Floor 8 (the bottom of the Ruined Wards) in Bethesda Susa.