"From two waters make one — Dissolve the bodies in the waters."
“Solutio is the operation whereby the solid material is washed clean in water or mercury so that all impurities are dissolved and the old form ceases to exist. It is often a repeated wash that gradually cleans and refines the material. One can see in alchemical images how the king and the queen together descend into a basin of water. In herbal alchemy, it is primarily herbal matter that has been burnt to ashes, but has not yet turned completely white, which is dissolved in distilled water. This takes place in a hermetically sealed beaker before the salt undergoes further operations. In the alchemy of the psyche, the operation often involves the conscious self descending and dissolving until it almost drowns in the primordial ocean of the unconscious. In metaphysical alchemy, solutio is a dissolution of an entity’s flowing mercurialis whereby everything returns to its primordial source. The old self drowns in the archetypal Self on the microcosmic level and the soul drowns in the world soul – anima mundi – on a macrocosmic level. When the self or soul is dissolved, it can then rise in a renewed, refined and spiritualised form.” - Alchemy – the divine work
Behold, the fiery Lion devours the shining Sun from the sky, And the splendid nymph brings forth her flowers. Thence the fiery man will sweat, and by fire he will loosen All his body immediately into moisture. Dissolve the mastery prepared from the said lime, So that Mercury may rise under favorable auspices.
The King and the Queen symbolize the male and female principles (sulfur and mercury) that must be united, while the bath signifies the process of dissolution or "washing" (solutio), and the descending bird (dove) typically symbolizes the spirit or the process of animation (quickening) of the matter.
"The reduction of bodies to the prime matter." Thesaurus thesaurorum, ca. 1775. Yale University Library