OF THE COLOURS IN THE FEATHERS OF CERTAIN BIRDS.
There are many birds in various regions of the world on whose
feathers we see the most splendid colours produced as they move, as
we see in our own country in the feathers of peacocks or on the
necks of ducks or pigeons, &c.
Again, on the surface of antique glass found underground and on the
roots of turnips kept for some time at the bottom of wells or other
stagnant waters [we see] that each root displays colours similar to
those of the real rainbow. They may also be seen when oil has been
placed on the top of water and in the solar rays reflected from the
surface of a diamond or beryl; again, through the angular facet of a
beryl every dark object against a background of the atmosphere or
any thing else equally pale-coloured is surrounded by these rainbow
colours between the atmosphere and the dark body; and in many other
circumstances which I will not mention, as these suffice for my
purpose.
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