The demon Bathin appears in the grimoires The Discoverie of Witchcraft, The Grand Grimoire, Pseudomonarchia Daemonum, and The Lesser Key of Solomon
From The Lesser Key of Solomon, Crowley/Mathers edition:
The Eighteenth Spirit is Bathin. He is a Mighty and Strong Duke, and appeareth like a Strong Man with the tail of a Serpent, sitting upon a pale-coloured [Horse?]. He knoweth the Virtues of Herbs and Precious Sontes, and can transport men suddenly from one country to another. He ruleth over 30 Legions of Spirits. His Seal is this which is to be worn as aforesaid.
The demon Barton may be the same as this demon.