I have been
lately inform'd, that an Observation near of Kin to Ours, has been made by
some Learned Men in _France_ and _Italy_, by long Exposing to a very Hot
Sun, two pieces of Marble, the one White, the other Black; But though the
Observation be worthy of them, and may confirm the same Truth with Our
Experiment, yet besides that our Tryal needs not the Summer, nor any Great
Heat to succeed, It seems to have this Advantage above the other, that
whereas Bodies more Solid, and of a Closer Texture, though they use to be
more Slowly Heated, are wont to receive a Greater Degree of Heat from the
Sun or Fire, than (_Caeteris paribus_) Bodies of a Slightest Texture; I have
found by the Information of Stone-cutters, and by other ways of Enquiry,
that Black Marble is much Solider and Harder than White, so that possibly
the Difference betwixt the Degrees of Heat they receive from the Sunbeams
will by many be ascrib'd to the Difference of their Texture, rather than to
that of their Colour, though I think our Experiment will make it Probable
enough that the greater part of that Difference may well be ascrib'd to
that Disposition of Parts, which makes the one Reflect the Sunbeams Inward;
and the other Outwards.
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