In the early 20th century, Henry Norris Russell proposed that, rather than being a new element, the line at 500.7 nm was due to a familiar element in unfamiliar conditions.
I det tidlige 20'ende århundrede foreslog Henry Norris Russell, at linjen ved 500,7 nm snarere end at repræsentere et nyt grundstof kunne skyldes et kendt grundstof under ukendte betingelser.