Fantastic gears, and probably the first reliable derailleur system.
Originally a French invention in 1924, they founded a British arm of the company, as illustrated by your wonderful catalogue above, in 1932.
I have a first generation 2-speed version, but it's not fitted on a bicycle.
If you interested in early gear systems, the 'Disraeli Gears' site is very useful and informative:
“You know how the title came about - Disraeli Gears - yeah? We had this Austin Westminster, and Mick Turner was one of the roadies who’d been with me a long time, and he was driving along and Eric (Clapton) was talking about getting a racing bicycle. Mick, driving, went ‘Oh yeah - Disraeli...
www.disraeligears.co.uk
Henri Desgrange (founder of Le Tour de France) infamously forbade the use of derailleurs in the race until 1937.
His words:
"I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailleur? We are getting soft... As for me, give me a fixed gear!"
I am now well over 45, I think it's time I embraced the derailleur perhaps.