Various devices were used to try to stiffen the tubes. Hetchins introduced the curly rear stays - seat and chain - and this gimmick became very popular.
what??!!
Where did the author get the idea that Hetchins curly stays (a.k.a. "vibrant" stays) were intended to stiffen the frame?
Other than this odd assertion, I enjoyed the review of this period of odd British frame features.
I recommend looking up images of the Paris-Galibier frame and the Flying Gate designs, both of which were efforts to shorted the wheelbase.
I do have one picture of a Bates with the funky dual curve "Diadrant" fork, displayed by Ken Wallace at a Classic Rendezvous gathering:
high resolution version
I don't have any pics of the Thanet Silverlight, but Peter Weigle has one on his flickr pages...
He has captioned it "what were they thinking?".
Changing subjects... nice to see an article by Sheldon Brown! Like Frank Berto, he wrote a lot of interesting and informative articles over the years!
Steve in Peoria (keeper of a Hetchins with curly stays)