There’s a wonderful scene in the March section of The Essex Serpent where Cora Seaborne and William Ransome are walking through the village and come to the riverbank; one of the barges seen out in the estuary appears to double in size and develop sails that it never had before. Both of them are aware that they have seen something special, but it doesn’t take long for the ever rational Ransome – unusual for a Victorian vicar – to have explained it all away as a form of mirage called a Fata Morgana.
Unlike many other forms of mirage, a Fata Morgana is so called because it significantly distorts the original image, forming a mirage that looks nothing like the original object; so the barge would transform into a three-masted man’o’war in full sail rather than just appear upside down in the air, for example. There are suggestions that the legend of The Flying Dutchman, the ghost ship that can never go home, is a Fata Morgana; they are rare and unusual sights, although they can be seen anywhere where the atmospheric conditions are right.
This begs the question of whether the Essex Serpent is a mirage, rather than either a genuinely prehistoric creature (as Cora believes, which would make it another version of the Loch Ness Monster if it existed) or completely imaginary (as Ransome has always maintained). If it were shown to be a mirage, the locals would understand that although they were not imagining things but that the threat was not real; and it would also prevent the village from being overrun by well-meaning amateur scientists intent on capturing the beast.
I’m still in the middle of the book and I have no idea whether the Essex Serpent is a mirage or not. Part of me hopes that it is, because it would allow everyone to save face; but there is much more to this story than just a submerged creature which I must admit I’m enjoying a lot more.