E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
In old astrology, a planet was said to be in its exaltation when it was in that sign of the zodiac in which it was supposed to exercise its strongest influence. Thus the exaltation of Venus is in Pisces, and her dejection in Virgo.
And thus, God wot, Mercry is desolate
In Pisces, wher Venus is exaltate.
Chaucer; Canterbury Tales, 6,285.
In chemistry, the refining or subtilising of bodies, or of their qualities, virtues, or strength.