Odorless, colorless, inert gas which gives off a peach colored light under high voltage m.p. below -272.2 ºC; -458.0 ºF b.p. -268.934 ºC; -452.081 ºF density 0.0001785 g/cc; 0.01114339 pound/cubic foot	memory peg
	1895 Sir William Ramsay, England, and independently by Per Theodor Cleve & Nils Langlet, Sweden
	Ήλιος (hèlios) = the Sun (Greek) named by Sir Norman Lockyer in 1869

The French astronomer Pierre-Jules-César Janssen (1824-1907) went to India to observe the 1868 total solar eclipse and to make the first spectroscopic study of the sun's chromosphere. He noted a yellow spectral line which did not quite match Sodium or any other element.
That same year, the English astronomer Sir Norman Lockyer (1836-1920) observed a yellow line in the solar spectrum that did not correspond to the known D₁ and D₂ lines of Sodium, and so he named it the D₃ line. Lockyer concluded that this new line was caused by an element in the Sun that was unknown on Earth; he and the chemist Sir Edward Frankland (1825-1899) proposed the name Helium, after the Greek Ήλιος [hèlios] = the sun (note).

Mary Elvira Weeks says that in the light of present knowledge the name Helium is a misnomer, for it has the suffix -ium which is characteristic of the names of the metals.

The search for this new element in the Earth was not very productive until 1895, when Sir William Ramsay (1852-1916) was told by Henry Meirs, at the British Museum, that, on heating, a Norwegian mineral cléveite (clevite) gave off a gas that Meirs though might be nitrogen. Ramsay thought that it might be a compound of argon. In two days, he showed that it was a new inert gas, helium. In this gas spectrum the bright yellow stripe appeared, proving the existence of hellium on Earth. It was independently discovered in clevite by the Swedish chemists Per Theodor Cleve (1804-1905) and Nils Langlet (1868-1936) about the same time.

Helios [Ήλιος], son of Hyperion and Theia, is the Greek god of the sun. Each morning at dawn he rises from the ocean in the east and rides in his chariot, pulled by for horses — Pyrois, Eos, Aethon and Phlegon — through the sky, to descend at night in the west. He sees and knows all, and was called upon by witnesses. He was represented as a youth with a halo, standing in a chariot, occasionally with a billowing cloak. For more information, see: Encyclopedia Mythica.

Soon after Ramsay separated Helium and proved that it was chemically inert, similar to Argon, Carl Runge and Louis Paschen, wrote that Helium consists of the mixture of two gases: Orthohelium (= Helium) and Parahelium; one of them with a yellow spectral line, the other with a green line. They proposed to name the second gas Asterium, from the Greek astros = starry. Ramsay and Travers proved that it is erroneous, since the color of the spectral line of Helium depends on the gas pressure.

After Helium was discovered by means of spectroscopical analysis of the total solar eclipse of 1868, astronomers began to point their telescopes at distant stars and nebulae. Their findings were scrupulously published in astronomical yearbooks, and some even found their way into chemical journals. These were findings which treated of alleged discoveries of new elements, which were given names such as Coronium (see Iron), Geocoronium (see Nitrogen), Nebulium (see Oxygen), Archonium, and Protofluorine (see Oxygen). Apart from their names, chemists knew nothing about them. But bearing in mind the Helium story, they placed these celestial strangers in the Periodic System before Hydrogen or in the space between Hydrogen and Helium. However, finally it was found out that the unusual spectral lines originated from known elements in unusual conditions, and Helium stayed the only element discovered outside the earth.

Edward C. Pickering discovered ionized Helium lines in the hot star Zeta Puppis in 1896, and mistaked it for a form of Hydrogen. Later these lines are found in other hot emission line stars and Wolf-Rayet stars. Pickering was convinced that the lines were due to Hydrogen under unknown temperature and pressure conditions. What was then called the "additional hydrogen lines" or the Pickering series could be fitted to the Balmer formula, provided half integral quantum numbers were allowed. Sir Norman Lockyer called the spectrum of ionized Helium Proto-hydrogen (note).

• W. Ramsay, The Gases of the Atmosphere: The History of Their Discovery. London: Macmillan, 1915.
• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 757-764.
• Edelgasse. Gmelins Handbuch der anorganische Chemie, 8. Aufl.; System-Nummer 1 (1926).
• Univ. Coll. London, Dept. of Chemistry, The Discovery of Helium & Other Gases, (on-line).
• L. Vlasov & D. Trifonov, 107 Stories About Chemistry (transl. from the Russian by David Sobolev) 1970: How Astronomers Sent the Chemists on a Wild Goose Chase (on-line).