Related Clues:

• They're induced by magical incantations
• How one gets the letters of sorcery
• The magical way one deals with 21 across
• Does it need a 18 down to make them work?
• One gets letters and casts them
• How one gets letters from the sorcerer
• What one does with the letters in 17 across
• Cast by the sorcerer, and what he does if he's eductated enough
• May be cast by letter
• The witch is literate enough for them
• Get the letters for the witches
• What the witch deals with in her letters
• How one gets the letters that may be cast
• What the wizard casts is the letters; but not for 13 across
• Charms, incantations