English: A 85mm Chance Brothers Incandescent Petroleum Vapour Installation which produced the light for the Sumburgh Head lighthouse until 1976. The lamp (made in approx. 1914) burned vaporized kerosene (paraffin); the vaporizer was heated by a denatured alcohol (methylated spirit) burner to light. When lit some of the vaporised fuel was diverted to a Bunsen burner to keep the vaporizer warm and the fuel in vapor form. The fuel was forced up to the lamp by air; the keepers had to pump the air container up every hour or so. This in turn pressurized the paraffin container to force the fuel to the lamp. The "white sock" is in fact an unburnt mantle on which the vapor burned.