Screw nut in ampoule with Mercury (50 ml).
Discharge tubes with different gases. There is no mercury vapuor inside Ar tube and all gases has purity >99.9%. Samples where made for the University's element collection.
Some photos about making these tubes.
And some interesting demonstration: comparison of luminescence intensity for different gases (at the same current) and spectral lines of Helium (by reflection in the grating).
Etched Gold anf Platinum buttons.