It is the ceria that gives the light, yet a little more of it
will lower the luminosity.
The non-chemical reader is apt to be confused by the strange names and
their varied terminations, but he need not be when he learns that the
new metals are given names ending in _-um_, such as sodium, cerium,
thorium, and that their oxides (compounds with oxygen, the earths) are
given the termination _-a_, like soda, ceria, thoria. So when he sees a
name ending in _-um_ let him picture to himself a metal, any metal since
they mostly look alike, lead or silver, for example. And when he comes
across a name ending in _-a_ he may imagine a white powder like lime.
Thorium, for instance, is, as its name implies, a metal named after the
thunder god Thor, to whom we dedicate one day in each week, Thursday.
Cerium gets its name from the Roman goddess of agriculture by way of the
asteroid.
The chief sources of the material for the Welsbach burners is monazite,
a glittering yellow sand composed of phosphate of cerium with some 5 per
cent.
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