An antique spectroscope

I found this little jewel on an ebricabrac (Abracadabra?) site. Apparently it's a late 19th Century spectroscope ("scope de spectres des objets lumineuzes", as these things are called, I was told) It could be worth a few thousand (Bitcoin?), or so I'm told:

After delicately cleaning it up a bit:

And it still works, see this spectrum of an old strip light (TL tube. will this old bird still fly chasing 'modern' LEDs?):

Much, much more about this and how diffraction led to Modern Physics and what Ennio Morricone has to do with all of this (?????)