Pyramical_ (121.) _This and other Considerations formerly deliver'd,
Illustrated by Experiments with black and white Marble_ (122, 123.)
_Thirdly, from the Black appearance of Holes in white Linnen, and from the
appearance of Velvet stroak'd several ways, and from an Observation of
Carrots_ (124, 125.) _Fourthly, from the small Reflection from Black in a
darkned Room_ (125, 126.) _Fifthly, from the Experiment of a Checker'd Tile
expos'd to the Sun-beams_ (127.) _which is to be preferr'd before a Similar
Experiment try'd in_ Italy, _with black and white Marble_ (128.) _Some
other congruous Observations_ (129.) _Sixthly, from the Roasting black'd
Eggs in the Sun_ (130.) _Seventhly, by the Observation of the Blind man
lately mention'd, and of another mention'd by_ Bartholine (130.) _That
notwithstanding all these Reasons, the Author is not absolutely Positive,
but remains yet a Seeker after the true Nature of Whiteness and Blackness._
(131, 132.)

Experiments _in Consort, touching_ Whiteness _and_ Blackness.

_The first_ Experiment, _with a Solution of Sublimate, made White with
Spirit of Urine_, &c. (133, 134.)

_The second_ Experiment, _with an Infusion of Galls, made Black with
Vitriol_, &c. (135, 136.) _further Discours'd of_ (137.)

_The third_ Experiment, _of the Blacking of Hartshorn, and Ivory, and
Tartar, and by a further Calcination making them White_ (138, 139.)

_The fourth_ Experiment, _limiting the_ Chymist's _principle_, Adusta nigra
sed perusta alba, _by several Instances of Calcin'd Alabaster, Lead,
Antimony, Vitriol, and by the Testimony of_ Bellonius, _about the white
Charcoles of_ Oxy-cædar, _and by that of_ Camphire. (140, 141, 142.) _That