Early observation of a pearl chain effect in a magnetic field
R. Whytlaw-Gray, J. B. Speakman · 1921
Microscopic examination of an iron arc spike deposited on a glass surface revealed fine particles of iron compound arranged in short chain sections with a bead-like appearance. The researchers suggested that this formation may have its origin in the outer envelope of the arc flame where particles line up around the arc stream due to circular magnetism from the current.

