Greeting to all

This is first post from a total newbie. Sorry in advance if I violate protocol.

I have found a very old box of 12 metal framed, glass plates (85mm x 100mm).

They appear to be a commercial set intended for use in an image projector.

The images on the plates are B/W scenes of the Rhine River.

The following is on the top of each slide: "Der Rhine bei Koblenz" "Rhihe Do 239"
This is followed by a more specific description of the particular image.

At the bottom of each slide is "Ed. Liesegang, Dusseldorf".

I'd be most grateful if someone could provide information regarding these plates. And/or a source where I could do more research.

Thanks so much,

edunne02