The problem thus propounded is not solvable, even in fiction, unless it be by "fantastic" treatment.
"The Light of Scarthey"
Egerton Castle
But from solvo and volvo, of the third conjugation, we have ubilis, uble; as, solubilis, sol'uble, solvible or solvable; volubilis, vol'uble, rollable.
"The Grammar of English Grammars"
Goold Brown