The invention provides a display method and a display device. The apparatus judges a road surface condition associated with location information on the basis of the location information concerning a location on a road on which the mobile apparatus is traveling, acquired externally and road surface condition information depending upon a road surface condition of a road on which the mobile apparatus travels. A plurality of electrically conductive couplers are connected between the first connection sites and the second connection sites, with neighboring conductive couplers being spaced apart to define at least one flow channel. Feedwater that passes through the water-filled coils is turned into steam by heat from the combustion gas.