(Source: Southgate ARC)
There are a number of vintage radio and amateur radio related eBooks available for free download on the Gutenberg site
Among them is the 1922 edition of The Radio Amateur’s Handbook by A. Frederick Collins.
Jarno de Haan @PA3DMI tweeted this link that will display the books available:
http://www.gutenberg.org/ebooks/search/?query=radioA. Frederick Collins
https://en.wikipedia.org/wiki/Archie_Frederick_Collins