Historical cat's whisker designs

Crystal radios from the 1920s are possible to get hold of, but can be quite expensive. This is a collection of photographs and diagrams of crystal/cat's whiskers setups that I've managed to find. The materials used correspond with what was available at the time, glass, metal but also the first plastics, ebonite and bakelite - which would have felt very futuristic in these years.

On the right is a diagram of a vertical set up. This design doesn't seem to allow for positioning of the point contact, only the overall pressure - which is generally more important.