Various forms of cylindrical wick lamps are employed for illuminating lighthouses.  For reflectors the wick is nearly an inch in diameter. For the lens-light a more powerful and complicated lamp is used.  The oil is made to flow into the burners by various means.  The most simple is by placing the reservoir higher than the lamp, the oil thus flowing by its own gravity to the level required.  Mineral oil is now generally used, as being superior to rape-seed or sperm oil.  Olive oil is used in some foreign lighthouses; and at the Cape of Good Hope oil produced from the tails of Cape sheep is employed.  It is said to be far superior to all other oils for its brilliancy in burning.