Discovery of Helium
On August 18th, 1868, a yellow line with a wavelength of 587.49 nm was detected in the solar spectrum by French astronomer Jules Janssen—during a total solar eclipse in Guntur, India. This line was initially assumed to be sodium but on October 20th of the same year, English astronomer Norman Lockyer concluded it was caused by an element in the Sun unknown on Earth. Lockyer and English chemist Edward Frankland named the element with the Greek god of the Sun, Helios
Source: Gates, S. James, Jr., and Cathie Pelletier. Proving Einstein Right: The Daring Expeditions that Changed How We Look at the Universe. New York: Public Affairs, 2019
Image by NASA Goddard Space Flight Center under CC BY 2.0 license
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Full disclosure, I may occasionally borrow a sentence from Will Durant's Story of Civilization. I absolutely love that collection!