Phlogiston

Outside and between the celestial spheres is a turbulent, rainbow fog of flammable ether called the phlogiston. The phlogiston is a multicolor web holding the various systems within their crystal shells. The term phlogiston is applied equally to both the Multicolored medium and to the entire region surrounding the crystal spheres.

Phlogiston has a varying thicknesses and forms dense rivers between planet-sized objects((such as the spheres themselves)). Voyages moving along these paths of concentrated phlogiston discover that the greater the density of the flow, the faster a ship can move. A ship can speed up and slow down by penetrating deeper into or raising itself out of these phlogiston rivers. further, the speed of the ship is at least partially dependent on the surface area it presents ti the flow, so many ships carry sails to increase their speed on interstellar journeys.

Gravity works in the phlogiston the same way it does in wildspace, down in directed towards the major axis of the ship.

The ambient temperature on the phlogiston is about the same as a moderate summer day in the temperate regions of most worlds.

Phlogiston is none of of the recognized four elemental matters. It is neither air nor earth, fire nor water. It cannot be reproduced or brought inside the bounds of a celestial sphere. If an attempt is made, whether by physical or magical containment, the phlogiston inexplicably dissipates, leaving no trace. Phlogiston simply cannot exist within wildspace. Finally, phlogiston is a dangerously flammable, mush like old-soaked cotton, which poses its own problems. Any flame exposed to phlogiston causes the surrounding area (including the Phlogiston-laden air envelope of the ship) to burst into flame. This flame expands immediately to three times it normal diameter and inflicts three times its normal damage. For this reason any weapons which rely on a spark or flame are not used in the phlogiston.

Because of the nature of the phlogiston, all flaming light sources are extinguished by the crew before entering the flow. Phlogiston is radiant so no other lights are needed on the exposed decks. Below decks, or in rare (and haunted) Dark Regions or space, cold natural lights(moths or fireflies, fluorescent moss) or magical lights are used for illumination.