Highly efficient form of Ætherine matter refined from the ætheric medium by 20th Century Terran researcher Yul Brown. Thought to be an elemental form preceding Veridigen. It is made by a proprietary process for dissociating Æther residuum in a hyper gravimetric chamber. Brown's gas was the first of the ætherine substances isolated. The substance is used for transmutation of phlogestonic wastes into more benign substances.