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here. For in this book we often tell of
things (see note) that cause many people
who have not heard or seen them to marvel greatly.
[rubric] Of the variety of certain common things [/rubric]
Many of things may easily be perceived
but the reasons for them are deeply hidden.
Still, people marvel little at them because
they see them so often. Mercury
has such a nature that it can hold up a
stone, something that neither
oil nor water can do. For with those substances
the stone sinks to the bottom. Quicklime
heats up so much in cold water that a hand
cannot touch it. The rays of the sun bleach
hair, but they blacken a man's skin.
They also whiten cloth, make damp
earth to be hard and dry, and soften
hard wax. By them one can make cold water in a
vessel become warm. The sun's rays when they go through
a glass or crystal make fire. (see note) Scraping iron
against a stone can also cause a fire to be lit.
A cold wind can catch the fire and make it flare up and spread.