Being a lover & enthusiast of old
Valve/Tube radios and equipment, this is an element (No. 90) that was discovered to be VERY
useful, in adding to the
Tungsten filaments/heated-cathodes to GREATLY increase the Electron emissions of these tube plates/coils!

And would do so, at a much reduced/necessary temperature. Such filaments etc, became what was called '
Thoriated-Tungsten'.
The Thorium covering was only
1 Atom thick!! but that's all it took for 300-400% improvement in Electron emissions!
Thorium is a malleable silver colored metal, but slowly blackens under oxidization to Thorium-Dioxide (Th-O2) on the outside.
It is
RadioActive, and interestingly... the most stable Isotope (232) has a
Half-Life of over
14 Billion years!! which is slightly
older than the current calculated life of the Universe. It has/had many other uses in the past, and to-date.
