The Timaeus of Plato

6 7 A] TIMAI02.
part are formed too narrow for earth and water, and too wide
for fire and air: for which cause no one ever perceived any
smell of these bodies ;
but smells arise from substances which
are being either
liquefied or decomposed or dissolved or evaporated
: for when water is
changing into air and air into water,
odours arise in the intermediate condition ;
and all odours are
vapour or mist, mist being the conversion of air into water, and
vapour the conversion of water into air ;
whence all smells are
subtler than water and coarser than air. This is
proved when
any obstacle is placed before the passages of respiration, and
then one forcibly inhales the air : for then no smell filters through
with it, but the air bereft of all scent alone follows the inhalation.
For this reason the complex
varieties of odour are unnamed,
and are ranked in classes neither numerous nor simple
:
2