The Fourth Theosophical Ray is the Ray of beauty and harmony. Controlling it is the entity Mahachohn who it seems has authority like a Prime Minister over the Third to Seventh Rays since they each affect in some way the mind, bliss or activity. The Masters of these Rays are similar to ministers of his Cabinet. Master Serepis, a Coptic Greek works on it. The Ray also referred to as the Green Ray because of its strong influence or association with the natural world in promoting both physical and artistic beauty. A.G.H.
Ellwood, Robert. Theosophy: A modern expression of the wisdom of the ages. Wheaton, IL. Quest Books. 1994. pp. 142