Whilst browsing through some vintage guide books, I came across this curious vintage advertisement. It's advertising something called the "Silent Guide" which boasts itself to be ...
A novel invention coupled with specially prepared itineraries for imparting and retaining information in a particular and pleasing manner about the many places of interest you may either visit or pass en route on your favourite motor coach tours.
I have tried to find some more information about this device, but have not managed to find anything at all. The perfect solution for not wanting to show one's ignorance of not knowing something, whilst at the same time not wanting to ask anyone.
Vintage advertisement, c.1922