Hi Tim, is there any date code marking on your Atlas neon glow lamp? 1940's looks about right though.
Atlas fluorescent tubes are indeed remarkable devices. They featured an exclusive Braided cathode design (also used in Thorn, Mazda, Omega, Ecko tubes, which were all made in the same factory as the Atlas products). Instead of being made from a simple coiled tungsten wire, their cathodes were braided into a hollow tube from seven fine wires of tungsten. The emissive compound was held inside this tube particularly strongly, resulting in exceptional lifetimes. Even though Atlas brand lamps have not been manufactured since the early 1970s, I recall when at University 10 years ago there were significant quantities of their fluorescent tubes still operating with more than 30 years service.
Perhaps for obvious reasons, the braided cathode was discontinued around the same time and the factory switched over to using a simple coiled tungsten electrode like the competition.