Abstract: Method and device for dissolving gas, especially carbon dioxide or compressed air, in liquid subject to conditions of pressure and temperature at which, when the solution is subsequently introduced into the combustion air, it will be in a supersaturated state and accordingly finely disperses and distributes itself uniformly. The fuel is forced by a pump (41) into the mixer (11), to which the gas is supplied through a flow regulator (29). Downstream of the mixer (11) are a turbulent section (163), a mixing dome (161), and an exhaust section (164) from which the solution is supplied free of bubbles to the carburetor or injector of an internal-combustion engine, a heating burner, or a reaction-engine burner. The flow regulator (29) is controlled in accordance with the throughput of fuel and regulated by a regulation device (R) in accordance with the percentage of gas in the mixing dome (161) as determined by a pressure gauge (46) or light sensor (51).