One reason that peat is, in general, inferior to wood in heating effect, lies in its greater content of incombustible ash.
"Peat and its Uses as Fertilizer and Fuel"
Samuel William Johnson
A heavy, colorless, incombustible gas.
"The Wonder Island Boys: Exploring the Island"
Roger Thompson Finlay
They pushed forward galleries formed of hurdles of green reeds, and oaken semicircles like enormous shields gliding on three wheels; the workers were sheltered in little huts covered with raw hides and stuffed with wrack; the catapults and ballistas were protected by rope curtains which had been steeped in vinegar to render them incombustible.
"Salammbo"
Gustave Flaubert