Take an eight ounce phial and three-parts fill it with water, and
place in it a healthy leech, changing the water in summer once a week,
and in winter once in a fortnight, and it will most accurately
prognosticate the weather. If the weather is to be fine, the leech
lies motionless at the bottom of the glass, and coiled together in a
spiral form; if rain may be expected, it will creep up to the top of
its lodgings, and remain there till the weather is settled; if we are
to have wind, it will move through its habitation with amazing
swiftness, and seldom goes to rest till it begins to blow hard; if a
remarkable storm of thunder and rain is to succeed, it will lodge for
some days before almost continually out of the water, and discover
great uneasiness in violent throes and convulsive-like motions; in
frost as in clear summer-like weather it lies constantly at the
bottom; and in snow as in rainy weather it pitches its dwelling in the
very mouth of the phial. The top should be covered over with a piece
of muslin.