Onimancy or onycomancy is a very elaborate practice of divination based on the observation of the Angel Urial. Oil of olive leaves is placed upon the right hand of an unpolluted boy or a young virgin girl. Or, even better is a mixture of walnut oil and tallow or blacking to be placed on the child’s hand. If money or things hidden in the earth are sought the young child’s face must be turned toward the east. If knowledge concerns a crime or of a person of affection then the face must be turned toward the south; for robbery toward the west; and for murder toward the south.
Then the child must repeat the seven-two verses of the Psalms, which the Hebrew Kabbalists collected for Urim and Thummim. These are found in the third book of Johann Rechlin on Kabbalistical art (De arte cabalistica, 1517), and the treatise De verbo mirifoco (c. 1480). In each of these verses occurs the venerable name of four letters, and the three lettered name of the seventy-two angels, which are referred to as the sacred name Shemhanphorash, which was hidden in the folds of the tippet of the high priest.
When the child or student had completely repeated all the verses he was told he would «see wonders.»
Other authorities believe that onycomancy refers to the interpretation of spots on human nails. A.G.H.
Source: 9.