Prof.dr Ing. J.F.J van den Brand, Sep. 2006 – 6
| The first
attempt seems to have come from ancient Greece where the four elements of
earth, water, air and fire were recognized. |
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| This scheme is
quite attractive at a trivial level and if you get bored during the rest of
the talk you could amuse yourselves constructing some of the objects around
us from these four elements. |
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| However during
the last few hundred years a more useful idea of elements developed.
Substances such as gold, sulphur, lead, nitrogen were recognized as elemental
in the sense that they were contained in different substances in different
mixtures but could not themselves be broken down further. |
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| By the beginning
of the last century Dalton had identified twenty elements and listed them
together with their relative weights. |
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