Nickel occludes hydrogen readily, is attacked by the halogen elements, and oxidizes easily when heated in air.
When molten, silver occludes the oxygen of the atmosphere, absorbing 20 times its own volume of the gas; the oxygen, however, is not permanently retained, for on cooling it is expelled with great violence; this phenomenon is known as the "spitting" of silver.
I try to set the end distance (at which the fog totally occludes everything) no lower than 4000.