What replaced tallow candles in lighthouses?

Tallow candles were replaced by sperm or colza oil, though both were expensive^[1]. The advances in refining petroleum, and the exploitation of its resources, led to 'earth-oil,' in some form, being employed for lighthouse purposes^[1].

The invention and improvement of the Argand burner further helped these efforts, and paraffin became universally utilized as the cheapest and most efficient illuminant known^[1].