I am not sure what “this book” you are referring to but did find the following which is very interesting. They were aware of radium experiments
It was the radium age of science fiction. Flask Gordon. I like the comparison to Star Trek Warp Drive which is common public knowledge today.
Even before Hiroshima, people knew the atomic bomb
http://publictabs.com/tabs/even-before-hiroshima-people-knew-the-atomic-bomb/
And HG Wells used the word atomic bomb in this 1914 book.
\http://www.gutenberg.org/files/1059/1059-h/1059-h.htm
Post number 4 was from “John Toland, The Rising Sun: The Decline and Fall of the Japanese Empire, 1936-1945”.
Interesting link. Thanks.