Signedunsigned
Inscribedstamped on side of glass [old Harvard Physics #?]: 8 7 [or maybe "B 7" or "g 7"]
on old sticker: N2O5 / 4.50
FunctionA gas discharge tube. When connected to a voltage source, a luminous arc extends from one electrode to the other. It is filled with an oxide of nitrogen, dinotrogen pentoxide.