One of the most versatile substances on Earth,
Why do we always take glass for granted?
A wine bottle, a pickle jar, a cheap vase,
A window pane, all disposable and recyclable.
The main ingredient is common sea shore sand,
Chemically combined with a little soda or potash.
Heat resistant glass - silica - is just pure sand.
For cut glass, add a little lead, for coloured glass, minerals.
Its greatest property is its sheer transparency,
Transparent because it is not crystalline.
It is in fact a paradox - a solid solution!
Consequently it lets light pass clean through it!
Like so many important scientific discoveries,
Penicillin, gravity, stainless steel, purple dye,
The steam engine, polythene and radioactivity,
Glass was discovered by pure accident!
In antiquity, sand and wood ash, combining
In the embers of a fire to produce shing jewels.
Homo Sapiens, sifting the jewels and concluding that they
Must be a fusion of wood ash and sand - discovered GLASS!
(John Knight UK - August 2009) .
John Knight
http://www.poemhunter.com/poem/a-touch-of-glass/
