Photo, left, anent irrational numbers: The symbol of the Ouroboros, the snake or dragon devouring its own tail, is the alchemical symbol par excellence of eternal recurrence. The alchemist-physicians of the Renaissance and Reformation were aware of the idea of eternal recurrence; the physician-philosopher Sir Thomas Browne in his A Letter to a Friend c. 1657 linked the Uroboros symbol with the idea of eternal return thus:
     . . . that the first day should make the last, that the Tail of the Snake should return into its Mouth precisely at that time, and they should wind up upon the day of their Nativity, is indeed a remarkable Coincidence, which tho Astrology hath taken witty pains to salve, yet hath it been very wary in making Predictions of it.
An allusion to eternal recurrence also occurs at the conclusion of Browne's The Garden of Cyrus: 
     All things began in order, so shall they end, and so shall they begin again;
JOHN BATCHELOR SHOW
Hour One
Sunday 17 May 2015 / Hour 1, Block A: The Irrationals, by Julian Havil  (1 of 4)
Sunday 17 May 2015 / Hour 1, Block B: The Irrationals, by Julian Havil  (2 of 4)
Sunday 17 May 2015 / Hour 1, Block C: The Irrationals, by Julian Havil  (3 of 4)
Sunday 17 May 2015 / Hour 1, Block D: The Irrationals, by Julian Havil  (4 of 4)
 
Hour Two
Sunday 17 May 2015 / Hour 2, Block A: The Party, by Richard McGregor (1 of 2)
Sunday 17 May 2015 / Hour 2, Block B: The Party, by Richard McGregor (2 of 2)
Sunday 17 May 2015 / Hour 2, Block C:  Bowing to Beijing, by William Triplett (1 of 2)
Sunday 17 May 2015 / Hour 2, Block D: Bowing to Beijing, by William Triplett (2 of 2)
 
Hour Three
Sunday 17 May 2015 / Hour 3, Block A: Chinese Aerospace Power, by Andrew Erickson (1 of 2)
Sunday 17 May 2015 / Hour 3, Block B: Chinese Aerospace Power, by Andrew Erickson (1 of 2)
Sunday 17 May 2015 / Hour 3, Block C: Heaven Cracks, Earth Shakes, by James Palmer (1 of 2)
Sunday 17 May 2015 / Hour 3, Block D: Heaven Cracks, Earth Shakes, by James Palmer (2 of 2)
 
Hour Four
Sunday 17 May 2015 / Hour 4, Block A: The Irrationals, by Julian Havil  (1 of 4)
Sunday 17 May 2015 / Hour 4, Block B: The Irrationals, by Julian Havil  (2 of 4)
Sunday 17 May 2015 / Hour 4, Block C: The Irrationals, by Julian Havil  (3 of 4)
Sunday 17 May 2015 / Hour 4, Block D: The Irrationals, by Julian Havil  (4 of 4)
 
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