... and how is Earth Not a Globe a scam? 
Read Markjos post:
We have been requested by the former secretary of the Zetetic Society to insert a series of papers in which he promises to show the nature of the deceptions practised by some at least among the advocates of the flat earth theory ED
...
I propose giving a detailed history in short weekly articles of the whole of what I shall allow myself to call the humbug catchpenny philosophy concocted by a man who styles himself Parallax otherwise Rowbotham alias Tryon, Gonlden, Dr Birley, etc.
Also read Flat Earth: History of an Infamous Idea by Christine Garwood. She talks about the possibility that Rowbotham was just using zeteticism as a scam, and that he was (probably) a serial scam artist before.