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Boyle, Robert, 1627-1691

"Experiments and Considerations Touching Colours (1664)"

And such a variety we have much more admired in that
lovely plant which is commonly, and not unjustly call'd the _Marvayl of
Peru_; for of divers scores of fine Flowers, which in its season that gaudy
Plant does almost daily produce, I have scarce taken notice of any two that
were dyed perfectly alike. But though _Pyro_: such things as these, among
others, keep mee from daring to affirm, that the Diversity and change of
Colours does _alwaies_ argue any great difference or alteration, betwixt,
or in, the Bodies, wherein it is to be discerned, yet that _oftentimes_ the
Alteration of Colours does signifie considerable Alterations in the
disposition of parts of Bodies, may appear in the Extraction of Tinctures,
and divers other Chymical Operations, wherein the change of Colours is the
chief, and sometimes the only thing, by which the Artist regulates his
proceeding, and is taught to know when 'tis seasonable for him to leave
off. Instances of this sort are more obvious in divers sorts of fruits, as
Cherries, Plums, &c. wherein, according as the Vegetable sap is sweetned,
or otherwise ripened, by passing from one degree to another of Maturation,
the external part of the fruit passes likewise from one to another Colour.


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