Meaning: much as I'd like it to mean spinning around until you fall over (which is what Rabelais appears to suggest), serious divination by this method apparently involves walking around a circle of letters... until you fall over. Or, more boringly, spinning a coin until it falls over. Cotgrave hedges his bets with 'divination by circles', which could apply to any number of things.
Usefulness: 1 (Could be applied to games of spin-the-bottle, but I'm going to talk to our safety person about how we can implement this at work; it'd be much more fun that tossing a coin. )
Logofascination: 3 (the concept is interesting, the word less so, and you're probably still digesting all that cheesecake from yesterday.)
In the wild: Nothing interesting.
Which is used in: the -mancy chapter, being G&P, Third Book, XXV: How Panurge consulteth with Herr Trippa.
By giromancy, if thou shouldst turn round circles, thou mightest assure thyself from me that they would fall always on the wrong side.Herr Trippa uses thou and thy in this chapter, reflecting the French familiar tous, tu etc; at the time, an insolent tone in either language. Unless you were a Quaker, in which case it was egalitarian.