Well, it took me awhile, but I'm pretty sure that this is where the theory I was talking about stems from. The book is "Vril:Power of the Coming Race" first published in 1871 and written by Edward Bulwer-Lytton.
The Vril-ya as an Aryan Race
According to the book:
"I arrived at the conviction that this people—though originally not only of our human race, but, as seems to me clear by the roots of their language, descended from the same ancestors as the great Aryan family, from which in varied streams has flowed the dominant civilization of the world; and having, according to their myths and their history, passed through phases of society familiar to ourselves,--had yet now developed into a distinct species with which it was impossible that any community in the upper world could amalgamate: And that if they ever emerged from these nether recesses into the light of day, they would, according to their own traditional persuasions of their ultimate destiny, destroy and replace our existent varieties of man."
In essence, the narrator believes the language of the Vril-ya to be of the same origin as Aryan languages. The passage does not outright affirm the narrator's belief that there is also an ethnic connection between the Vril-ya and the Aryans. In fact, subsequent passages have Zee, a female Vril-ya scientist, explain to the narrator that the Vril-ya are descended from frogs.
Many readers today find the passage quoted above to be thinly veiled admiration for the Vril-ya as Aryan Supermen. However, the modern connotations of these terms are heavily influenced by Nazi and White Supremacist propaganda developed and produced decades after the writing and initial publication of this book.
Therefore, while it is easy to see how fanatical readers were able to, in part, derive their Nazi and Supremacist beliefs and doctrines from this book, it is also important to note that The Coming Race says no more than it does say, and says even that as a work of fiction. Unlike with Zanoni, Edward Bulwer-Lytton made no suggestions about the work being non-fiction. A fact that, of course, did not stop many readers from assuming just that all the same.