Word Study
cæsium
CIDE DICTIONARY
cæsium, n. [NL., from L. caesius bluish gray.].
A rare alkaline metal found in mineral water; -- so called from the two characteristic blue lines in its spectrum. It was the first element discovered by spectrum analysis, and is the most strongly basic and electro-positive substance known. Symbol Cs. Atomic number 55. Atomic weight 132.6. [1913 Webster]
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