from The Century Dictionary.
- Belonging to or resulting from pneumatolysis or the action of gases contained in molten rock-magmas. The vapors or gases escaping from molten magmas may act as mineralizers in adjacent rocks and be a source of some ore deposits.
Sorry, no etymologies found.
It is probable that the temperature was so high as to cause the solutions to be gaseous rather than liquid, and that what have been called "pneumatolytic" conditions prevailed; but evidence to decide this question is not at present available.