Experimental study of the downward melting of a gas-releasing substrate solid surface by a hot liquid pool of different densities was performed. The molten phases of the solid and the liquid pool were mutually miscible. Heating of the liquid pool was obtained by a flat heater grid, suspended in the liquid above the solid surface. The liquid layer beneath the heater grid was thermally stable. After the onset of melting and gas release, the different flow regimes, identified in the case of nongas-releasing solid, were not encountered. The melting rate continuously increased with an increase in the ratio of the liquid density to the melted-solid density, ρ*, attaining a maximum at about ρ* ≈ 1.19, beyond which this rate decreased to even a lower value than that of nongas-releasing solid.