Fill a wine-glass with water, place over its mouth a card, so as to
prevent the water from escaping, and put the glass, mouth downwards,
into a basin of water. Next, remove the card, and raise the glass
partly above the surface, but keep its mouth below the surface, so that
the glass still remains completely filled with water. Then insert one
end of a quill or reed in the water below the mouth of the glass, and
blow gently at the other end, when air will ascend in bubbles to the
highest part of the glass, and expel the water from it; and, if you
continue to blow through the quill, all the water will be emptied from
the glass, which will be filled with air.