Curious things happen out on the ocean. Some of these natural phenomena are illustrated in detail in Philip Henry Gosse’s compendium The Ocean from 1854. As part of their recent releasing of more than a million images into the public domain through Flickr, the British Library shared a few of these strange occurrences in their 19th century glory, and out on the seas you can still sometimes witness the otherworldly spectacles with your own eyes.

Fata Morgana

Distortions of Irregular Refraction (via British Library)

A common high seas illusion is the Fata Morgana — described as irregular refraction here. Similar to a desert mirage, the illusion of a ship flipped upside down on the horizon is caused by light bending through temperature variations in the air, turning the atmospheric duct into a refracting lens. Sometimes this phenomenon causes ships to appear to be floating like phantoms above the waves. The Fata Morgana even had an influence on the legend of the ghostly Flying Dutchman, as Atlas Obscura’s Annetta Black detailed in an article.

A contemporary Fata Morgana (photograph by Timpaananen/Wikimedia)

Submarine Volcano



Submarine Volcano (via British Library)



Sometimes 19th century voyagers were startled to see a cataclysmic eruptions from the depths. Submarine volcanoes are incredibly active, contributing some 75% of the Earth’s magma each year, although many we never sea. Those nearer to the surface, however, burst from their underwater fissures visibly, sometimes with harrowing results. In 1650 some 70 people were killed when the Kolumbo underwater volcano erupted.

The underwater West Mata Volcano in the Pacific Ocean (via NOAA Photo Library)

Aurora Borealis



Aurora Borealis (via British Library)



You might think the ethereal lights of the Aurora Borealis are only witnessed over land, but they’re also visible in the skies over the ocean. The waves of vivid light are best witnessed in the Arctic or Antarctic seas, where there is the most colliding of particles and atoms in the atmosphere.

Aurora Borealis over the Pacific (photograph by Jason Jenkins)

Mock Suns



Mock Suns (via British Library)



Mock suns, also known as sun dogs and officially as parhelia, are the startling occurrence of sort of impostor suns in the sky. However, it is not actually another star suddenly looming into our solar system, but a refraction in the clouds on ice crystals that form in cold temperatures.

Fargo, North Dakota, sun dogs (photograph by Gopherboy6956/Wikimedia)

The Southern Cross



The Southern Cross (via British Library)

Not quite an earthly phenomenon, but this depicts the clarity with which you can see the greater existence outside of our planet out in the clear space of the ocean. The Southern Cross, officially known as the Crux, is a small constellation most visible from the southern hemisphere, and an icon to travelers on the waters far from home.

Deep space photograph of the Southern Cross (via Wikimedia)

Waterspouts



Waterspouts (via British Library)

A little more terrifying, well, maybe just behind the underwater volcano, is the waterspout. Basically a tornado that has formed over water, the water from the clouds connects through the funnel to the water, causing a winding whip of watery horror. One can only imagine what this and the other ocean phenomena appeared like to voyagers venturing out to the seas with only their rickey wooden boat to accompany them into the unknown.

Waterspout off the Florida Keys (via NOAA)