It was later shown that the lines resulted from the presence of helium; a gas that was discovered in 1868.
== Zunanje povezave ===== Osmrtnice ===* AN 172 (1906) 111//112* ApJ 25 (1906) 53* Obs 29 (1906) 332 (en odstavek)* PASP 18 (1906) 280 (on stavek)