1660 Urquhart tr. Rabelais Gargantua & Pantagruel iii. xxv.
By Giromancy, if thou shouldst turn round Circles, thou mightest assure thy self from me, that they would fall always on the wrong side.
1868 Chambers's Encyc. V
GYROMANCY..was a method of divination by means of a circle, and was generally performed in the following manner: the soothsayer described a circle, and marked it all round with letters; then he commenced to walk round the circle, repeating his incantations, and at the places where he stopped the letters were carefully noted, and by the interpretation put upon these letters, the answer of the god was obtained.
1953 Gaynor (ed.) Dict. Mysticism
Gyromancy: Divination by having a person walk around a chalked circle until he collapses and observing the position of his body relative to the circle.