Forcas

Forcas - In occult lore it is not indicated what rank Forcas once held in the angelic hierarchy, or to what order he belonged; but he is a fallen angel; in Hell he is a renowned president or duke; and here he devotes his time to teaching rhetoric, logic, and mathematics.  He can render people invisible; he knows also how to restore lost property.  De Plancy, Dictionnaire Infernal, calls Forcas a chevalier of the infernal kingdom, with 29 legions to do his bidding.  His sigil is shown in Waite, The Book of Black Magic and of Pacts, p.175. [Rf. Scot, Discoverie of Witchcraft; Wierus, Pseudo-Monarchia.] A Louis Breton engraving of Forcas is reproduced in Seligmann, The History of Magic, p.230.  (a)

The grand president of Hell, a robust, white-haired old man, was Forcas.  He taught logic and rhetoric, and commanded 29 legions of the infernal forces.  (c)

Foras, alias Forcas is a great president, and is seene in the forme of a strong man, and in humane shape, he understandeth the vertue of hearbs and pretious stones: he teacheth fullie logicke, ethicke, and their parts: he maketh a man invisible, wittie, eloquent, and to live long; he recovereth things lost, and discovereth treasures, and is lord over nine and twentie legions. (g)

FORAS. - The Thirty-first Spirit is Foras. He is a Mighty President, and appeareth in the Form of a Strong Man in Human Shape. He can give the understanding to Men how they may know the Virtues of all Herbs and Precious Stones. He teacheth the Arts of Logic and Ethics in all their parts. If desired he maketh men invisible, and to live long, and to be eloquent. He can discover Treasures and recover things Lost. He ruleth over 29 Legions of Spirits, and his Seal is this, which wear thou, etc. (h)

Resource List - all entries are taken verbatim from the original source:

(a) "The Dictionary of Angels" by Gustav Davidson, © 1967

(c) "Fallen Angels...and Spirits of the Dark" by Robert Masello ©1994. 

(h) The Lesser Key of Solomon.  GOETIA.  Compiled and Translated By S.L. "MacGregor" Mathers.  Editing and Additional Material By Aleister Crowley

(g) Pseudomonarchia daemonum - Johann Wier (1583)