French Astronomer Pierre Janssen discovers helium in solar spectrum during eclipse
On August 18, 1868
60-70ft sea serpent sightings reported offshore in Gloucester, Massachusetts
On August 18, 1817
- 1572 Henry of Navarre (later Henry IV of France) marries his cousin Margaret of Valois in Paris
- 1782 Romantic Age poet and artist William Blake (24) marries Catherine Boucher, 5 years his junior, in St. Mary's Church, Battersea, London.
- 1918 Italian tenor Enrico Caruso (45) weds socialite Dorothy Benjamin (25)