How did lighthouse technology evolve?

The ancients used tall columns with fires of wood or coal in open grates, or oil lamps^[1]. Mediaeval lighthouses in England were similar, though some used candles or oil lamps within towers^[1].

After the Reformation, coal or wood fires became common, but enclosing them in lanterns with a funnel saved fuel at the expense of light quality^[1]. Candles were used at Eddystone due to the lack of space for fuel^[1]. Oil lamps were re-adopted around the mid-18th century, with reflectors being introduced to increase light intensity^[1]. Argand's cylindrical-wick lamps and lenses further improved the system^[1]. Gas and electricity were later adopted^[1].