The 'Infanta' of _A25_, _O'F_, _Q_ is pretty certainly right, though 'Infant' can be applied, like 'Prince', to a woman. There is probably a second allusion to the claim of the Infanta of Spain to be heir to the English throne.
l. 60. _heavens Scheme_: 'Scheme' is certainly the right reading. The common MS. spelling, 'sceame' or 'sceames', explains the 'sceanes' which _1633_ has derived from _N_, _TCD_. For the _Satyres_ the editor did not use his best MS. See _Text and Canon, &c._, p. xcv. It is possible that a slurred definite article ('th'heavens') has been lost.
In preparing his 'theme' or horoscope the astrologer had five principal things to consider, (1) the heavenly mansions, (2) the signs of the zodiac, (3) the planets, (4) the aspects and configurations, (5) the fixed stars. With this end in view the astrologer divided the heavens into twelve parts, called mansions, to which he related the positions occupied at the same moment by the stars in each of them ('drawing the horoscope'). There were several methods of doing this. That of Ptolemy consisted in dividing the zodiac into twelve equal parts. This was called the equal manner. To represent the mansions the astrologers constructed twelve triangles between two squares placed one within the other. Each of the twelve mansions thus formed had a different name, and determined different aspects of the life and fortune of the subject of the horoscope. From the first was foretold the general character of his life, his health, his habits, morals. The second indicated his wealth; and so on. The different signs of the zodiac and the planets, in like manner, had each its special influence. But sufficient has been said to indicate what Donne means by 'drawing forth Heavens scheme'.
l. 62. _subtile-witted._ There is something to be said for the 'supple-witted' of _H51_ and some other MSS. 'Subtle-witted' means 'fantastic, ingenious'; 'supple-witted' means 'variable'. Like Fastidious Brisk in _Every Man out of his Humour_, they have a fresh fashion in suits every day. 'When men are willing to prefer their friends, we heare them often give these testimonies of a man; He hath good parts, and you need not be ashamed to speak for him; he understands the world, he knowes how things passe, and he hath a discreet, a supple, and an appliable disposition, and hee may make a fit instrument for all your purposes, and you need not be afraid to speake for him.' _Sermons_ 80. 74. 750. A 'supple disposition' is one that changes easily to adapt itself to circumstances.