The first man known to use a signal other than a bonfire used a chandelier. He was lord of a castle that stood near a rocky seacoast. He hang the chandelier, 1.__________ containing many large tallow candles, in the highest tower of his castle. Thus he warned passing ship from 2.__________ the danger along the coast.
Candles soon became the common fuel for signal lights. They were later replaced by oil lamps, that 3.__________ could burn larger and brighter. Kerosene and gas lamps 4.__________ also tried. These are still in use now in some smaller lighthouses. But today most lighthouses sent electric 5.__________ light blazing out over the sea.
The ancient fire signals only say "Danger! Keep off!". But the modern lighthous also identifies it in a code 6.__________ known to all shipping. Most of the great lights have their own special signals. The light may be one that blinks--as a giant firefly in the night. Or it may be 7.__________ a revolved light that is red then green. Or it may be 8.__________ only white. But however the signal, it is sent very 9.__________ regularly. A ship within its ranges is never at a loss to know which lighthouse it is, and where it is being 10.__________ located
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