19.503 - Advanced History Solution

• Weisse masse is an old German term for the element bismuth.
• Seolfor and siolfur are forms of the old Anglo-Saxon word for the element silver.
• The element Promethium is named for the mythological figure Prometheus
  
• Nitron is an old Greek form of the name for the element nitrogen.

The atomic numbers of these elements are 83, 47, 61, and 7. They are all prime numbers, and specifically they are the 23rd, 15th, 18th, and 4th prime numbers. Convert those numbers to letters of the alphabet to spell WORD.

The answer is WORD.