Several times when I am using a classic camera people are surprised by the fact that they have a self-timer to delay the shutter. I think that 'time' is becoming something digital and they don't connect immediately time and mechanisms. Well, actually as soon as the amateur reached to the image making there was a need to allow the photographer to be part of the scene. Sophisticated shutters had a built in timer but for the popular cameras there was this kind of device featured in this page that could be set to slowly push the cable release button.



This one was produced by Ernemann and it is a hard to find item. To use it you turn the black wheel to cock it and when revolving back it presses the button. The way it holds it you can see in this picture. But not only that, once it went all the way it releases it just like your fingers would also do.



This is a more available timer with the same features.



The owners manual.



And also an advertising from a German book
Knipse Aber Richtig, von Wolf H.Döring DWB 1931