Note 1. Trepidation of the spheres: A motion which the Ptolemaic system of astronomy ascribes to the firmament to account for certain phenomena, really due to the motion of the axis of the earth. (Century Dictionary.) [back]
Note 2. As stiff twin compasses are two: To the comparison of a man that travels and his wife that stays at home with a pair of compasses, it may be doubted whether absurdity or ingenuity has better claim. (Dr. Johnson, Lives of the English Poets; Cowley.) This figure of the compass is said to have been suggested by the impresa of old John Heywood, Donnes maternal grandfather. (Schelling, A Book of Elizabethan Lyrics.) [back]
Note 3. Lines 2536, If they be two: These stanzas inspired Dr. Johnsons famous passage on the metaphysical poets, a phrase which it is said he borrowed from a hint of Drydens. [back]