|Praseodymium-core carbon rods.|
Rods like this (about 1/2" diameter) are used, or at least used to be, in the motion picture industry to create large amounts of light for filming. They contain a core (visible in this photo) of a mixture of rare earths which, when vaporized in the arc, provide a daylight spectrum of light. This use is very similar to the way the rare earths provide daylight spectrum light in modern sealed arc lights, just out in the open air.
Source: eBay seller saturngroup
Contributor: Theodore Gray
Acquired: 16 April, 2009
Text Updated: 17 April, 2009