What Contraption is This?

This picture was taken around 1922. My first guess was a loudspeaker of some kind, perhaps used to address large crowds. I was wrong.  

The answer is in the full caption at Weird Universe. The gadget was found in a book called Illustrated World, published in 1922-1923. You don’t see such machines much these days, because the whole idea seems futile.

Source: neatorama