"According to this invention the progressive feeding of the combustible liquid into the air reservoir is dependent upon the fall of pressure in the latter. For this purpose I so arrange the pipe connecting the fuel-reservoir with the air-reservoir that instead of being simply connected to the bottom of the former it extends internally throughout the whole or fair proportion of the vertical height of the fuel-reservoir and has two or more openings at different heights permitting communication between the interior of the pipe and that of the vessel…"