He used a 12 inch (30 cm) "burning lens" to focus the sun’s rays and heated mercuric oxide. He noticed that “a most remarkable gas was emitted”. In this gas he found that a candle burned ...

It was first isolated in 1808 in England when Sir Humphry Davy electrolyzed a mixture of lime and mercuric oxide. Today we obtain calcium through the electrolysis of a fused salt such as calcium ...