I want to know the answer to the following question:
What was the problem with manufacturing the tungsten filament?
All the background I'm provided with is that "It was found that very pure tungsten formed filaments that sagged in use, and that a very small "doping" treatment with potassium, silicon, and aluminium oxides at the level of a few hundred parts per million greatly improved the life and durability of the tungsten filaments.". Is that enough to answer the question?