Automation and Decline
For most of their history lighthouses were staffed. Keepers trimmed wicks, wound the clockwork that turned the lens, sounded fog signals, logged weather, and in many jurisdictions were expected to assist in rescues. Rock stations rotated crews on tours of duty measured in weeks, and the isolation of the work produced an extensive body of memoir and folklore.
Mechanisation eroded the role steadily. Electric illumination removed the need to tend a flame. Acetylene systems developed by the Swedish engineer Gustaf Dalén around 1907, including a sun valve that extinguished the light automatically at dawn, made genuinely unattended operation practical and won him the 1912 Nobel Prize in Physics. Later, solar panels and sealed-beam lamps reduced maintenance further.
The deeper change was navigational. Radio direction finding, then radar, then satellite positioning systems supplied continuous and far more precise fixes than a visual bearing on a flashing light. Authorities began decommissioning or destaffing stations in large numbers through the second half of the twentieth century. The last officially staffed lighthouse in the United States, Boston Light, retained keepers by statute long after the practical need had passed.