He"li*um (hē"l&ibreve;*ŭm),
n. [NL., fr. Gr. "h`lios the sun.]
(Chem.) An inert, monoatomic, gaseous element occurring in
the atmosphere of the sun and stars, and in small quantities in the
earth's atmosphere, in several minerals and in certain mineral waters.
Symbol, He; at. wt., 4. Helium was first detected
spectroscopically in the sun by Lockyer in 1868; it was first prepared
by Ramsay in 1895. Helium has a density of 1.98 compared with
hydrogen, and is more difficult to liquefy than the latter.
Chemically, it belongs to the argon group and cannot be made to form
compounds. It is a decomposition product of the radium
emanation.
He"li*um (?), n. [NL., fr. Gr. &?; the
sun.] (Chem.) A gaseous element found in the atmospheres
of the sun and earth and in some rare minerals.
He"li*um (hē"l&ibreve;*ŭm),
n. [NL., fr. Gr. "h`lios the sun.]
(Chem.) An inert, monoatomic, gaseous element occurring in
the atmosphere of the sun and stars, and in small quantities in the
earth's atmosphere, in several minerals and in certain mineral waters.
Symbol, He; at. wt., 4. Helium was first detected
spectroscopically in the sun by Lockyer in 1868; it was first prepared
by Ramsay in 1895. Helium has a density of 1.98 compared with
hydrogen, and is more difficult to liquefy than the latter.
Chemically, it belongs to the argon group and cannot be made to form
compounds. It is a decomposition product of the radium
emanation.
