First published as articles in the Melbourne Herald, the articles (later republished in pamphlet form in 1875) claim to be an account of a journey into the islands. Cole sought to capitalize on the public fascination with the island to Australia's north. He responds to both the interest in New Guinea and Charles Darwin's evolutionary theory by claiming that a race of human beings with tails could be found within the New Guinea interior.
Source: Brawley, Sean and Chris Dixon. The South Seas: A Reception History from Daniel Defoe to Dorothy Lamour. Lexington Books, 2015.
The tribe of people characterised in the story is called the 'Elocwe', which is 'E. W. Cole' written backwards. The king of this tribe is 'Nannerb Siuol', 'Louis Brennan' spelt backwards - Brennan was a friend of Cole's. Furthermore, the name of the village inhabited by the Elocweans is 'Etihwretep' (Peter White) and the river in the story is 'Ramsderf' (Fred Smar[t]). White and Smart were employees of Coles.
(Source: Graham Stone. Notes on Australian Science Fiction. Sydney, New South Wales : The Author, 1991).