Continuing a discussion of odd stories of invisibility in fiction that I came across in writing my book on the history of invisibility physics.

Pulp stories are sometimes quite a ride. They can be filled with bizarre ideas and twists and turns that are often largely nonsensical, tailored to bring people back to read what happens in the next issue.

One spectacular example of this is The Sea Demons, by Victor Rousseau Emanuel, first serialized in All Story Weekly starting in January of 1916 and then published as a novel in 1924. In August of this year, Armchair Fiction released a reprint of this otherwise hard to find novel:

This book is a wild ride and, relevant to my interest, features an undersea species of near-invisible humanoids, who threaten to destroy the surface world!