Time and tide fail to diminish David Stevenson family's legacy

• AILSA Craig lighthouse in the Firth of Clyde was built in 1886 by engineers David Stevenson and Thomas Stevenson, father of Scottish author Robert Louis Stevenson.

The lighthouse operated by oil-burning light, which remained in use until 1911, when it was converted to incandescent light.

The lighthouse was automated in 1990 and is monitored from the Northern Lighthouse Board's offices in Edinburgh. In 2001, Ailsa Craig Lighthouse was converted to solar-electric power.

• The original Kinnaird Lighthouse at Fraserburgh was built in 1787 by Thomas Smith, the first engineer to the lighthouse board, and father-in-law to Robert Stevenson.

The original lighthouse operated until 1824, when internal alternations were made to the tower and additional buildings were constructed for the light keepers. In 1906, the light was converted to incandescent operation. The first radio beacon in Scotland was introduced at Kinnaird Head in 1929. The original lighthouse at Kinnaird Head is now home to the Museum of Scottish Lighthouses. An automatic light was established beside the original light in 1991.

• Cape Wrath Lighthouse, on the most north-westerly tip of the Scottish mainland, was built in 1828 by Robert Stevenson and manned until 1998. The automated lighthouse now overlooks the ruins of the Lloyd's signal station, which was first used to monitor vessels rounding the stormy cape. Cape Wrath lighthouse was converted to automatic in 1998. The main building is home to what is claimed to be Britain's most remote cafe.