In the book,
The Hermetic Museum, Alchemy & Mysticism, page 365 (Alexander Roob, published by Taschen), there's a picture attributed to M. Maier,
Atalanta fugiens, 1618. In the picture, two lions (one winged the other not) are going at each other.
Lions Pic
The caption reads:
" 'Add to the lion a winged lion so that both may live in the air. But it stops firmly and stands on the earth. This picture of nature shows you the way through which it rules.' Maier advises sublimating the two natures (Sulphur and Mercury) until they are inseperable."
This is an enigmatic statement, but I believe it's closely related to Waite's statement, "that desire which is not in Nature, but by which Nature is sanctified." The
rubedo (red) phase of the Work is also the
fixatio (fixation) phase. This explains how it can be both "in the air" and "on the earth." The
rubedo phase is often symbolized by a Phoenix in the old manuscripts. The red color represents life, or more precisely,
eternal life (note the red color of Waite's lion). The
fixatio phase is the final phase when the
lapis (stone) solidifies.