That's interesting, lights*plus

If the filtering of the green and the yellow mercury line, isn't complete, so this lamp don't made from wood glass, but just regular glass with a deep purple coloring.

These ARE made from Wood's Glass dor, just that it is not a perfect filter and/or it is very thin. What is interesting here is not only has George caught the 365nm mercury line at the far left, but also the phosphor continuum....YES, these use phosphors to convert some of the two mercury resonance lines at 184 and 257nm (which can't get through the glass) into a a broad peak centered at about 360nm. Traditionally Calcium Plumbous Metasilicate, (99CaSiO3:PbSiO3) was used for this purpose, but now there are a host of Rare Eatrh and/or Europium-II based phosphors, of which Strontium Europium Fluroborate, with a peak at 366nm, and Strontium Europium Pyroborate with a peak at 371nm are the most likely in this application. Their band width is quite broad, about 30-40nm wide, as can be seen above.

Here are some I know of:-

Ca(Pb-II)SiO3........360nm
Sr(Pb-IV)Al4O7.......313nm
Ba(Pb-IV)Si2O5.......355nm
Sr(Eu-II)B4O7........371nm
Ln(Ce-III)Al11O19....338nm (Ln=La-----Lu Natural Mixture Abundance)
Sr(Ce-III)MgAl10O17..307nm
Sr(Eu-II)B2F2O7......366nm

As you can see, some of these are rather short wavelength emitters in their own right, into the UVB part of the spectrum. These are generally used in printing lamps, insect attracting lamps, Psoriasis treatment lamps and BLB type lamps.

I see where you are going with this, Andrew. This specimen has some kind of UVC to UVA resonance conversion here with the coating inside the tube. The black/purple lacquer is probably a weak filter for the remaining visible light to block except for the strong Mercury green/yellow line here.

It is not a lacquer Robert, least I have never seen such a lacquer....no organic medium will last very long exposed to this level of UV flux...even if it is only UVA. These lamps are either solid Wood's Glass, but it is quite thin...particularly on the outside of the bends where it is in tension when bent, or it may be a ply glass, clear glass with a thin layer of Wood's Glass fused to the outside...but I doubt it.
If I ever get a broken one of these I will photograph the broken ends to prove it is SOLID Wood's Glass.

Most UVA lamps....even the high pressure mercury ones like the late model HPW's use these phosphors to beef up their UVA at the benifit of otherwise wasted UVC resonance lines. Michael, in Switzerland, has both types of HPW, (no phosphor on the left, phosphor on the right) running here.

Wait a minute, Andrew. Are you saying that there are at least two layers of glass that are fused together?

Yes, Robert...."samdwich glass" or "ply glass", 90% of the thickness is just plain glass and 10% is the coloured stuff. It is commonly done with red glass which contains a colloidal suspension of gold, and is thus expensive...so they use it sparingly. I have some red (transparent) incandescent lamps made using ply glass with a thin layer of red fused to a mostly clear bulb. Some infra red heat lamps have their faceplates done that way too.