thumb|Hydromancy may interpret the color, ebb and flow, or ripples of perturbed water
Hydromancy (Ancient Greek ὑδρομαντεία, water-divination, from ὕδωρ, water, It also refers to the entering of a trance by staring at a chosen form of water, which is a form of scrying.
Methods of hydromancy
There are various methods of hydromancy. Hydromancy with rain water was termed "hydatoscopy", and hydromancy with water from a spring was termed "pegomancy".
The Jesuit M. A. Del Rio (1551–1608) described several methods of hydromancy. The first method described depicts a ring hanging by a string that is dipped into a vessel of water which was shaken. A judgment or prediction is made by the number of times which the ring strikes the sides of the vessel.
A second method is when three pebbles are thrown into standing water, and observations are made from the circles that are formed when the objects strike the water.
Another method (and possibly the simplest) is via "scrying" (the entering into a trance as stimulated by staring at water in a bowl or some running form).
In Renaissance magic, hydromancy was classified as one of the seven "forbidden arts", along with necromancy, geomancy, aeromancy, pyromancy, chiromancy (palmistry), and spatulamancy (scapulimancy).