those of the former, and arose after this manner. The white round Spot
of Light in the middle of the Rings continued white to the center till
the distance of the incident and reflected beams at the Chart was about
7/8 parts of an Inch, and then it began to grow dark in the middle. And
when that distance was about 1-3/16 of an Inch, the white Spot was
become a Ring encompassing a dark round Spot which in the middle
inclined to violet and indigo. And the luminous Rings encompassing it
were grown equal to those dark ones which in the four first Observations
encompassed them, that is to say, the white Spot was grown a white Ring
equal to the first of those dark Rings, and the first of those luminous
Rings was now grown equal to the second of those dark ones, and the
second of those luminous ones to the third of those dark ones, and so
on. For the Diameters of the luminous Rings were now 1-3/16, 2-1/16,
2-2/3, 3-3/20, &c. Inches.
When the distance between the incident and reflected beams of Light
became a little bigger, there emerged out of the middle of the dark Spot
after the indigo a blue, and then out of that blue a pale green, and
soon after a yellow and red. And when the Colour at the center was
brightest, being between yellow and red, the bright Rings were grown
equal to those Rings which in the four first Observations next
encompassed them; that is to say, the white Spot in the middle of those
Rings was now become a white Ring equal to the first of those bright
Rings, and the first of those bright ones was now become equal to the
second of those, and so on. For the Diameters of the white Ring, and of
the other luminous Rings encompassing it, were now 1-11/16, 2-3/8,
2-11/12, 3-3/8, &c. or thereabouts.
When the distance of the two beams of Light at the Chart was a little
more increased, there emerged out of the middle in order after the red,
a purple, a blue, a green, a yellow, and a red inclining much to purple,
and when the Colour was brightest being between yellow and red, the
former indigo, blue, green, yellow and red, were become an Iris or Ring
of Colours equal to the first of those luminous Rings which appeared in
the four first Observations, and the white Ring which was now become
the second of the luminous Rings was grown equal to the second of those,
and the first of those which was now become the third Ring was become
equal to the third of those, and so on. For their Diameters were
1-11/16, 2-3/8, 2-11/12, 3-3/8 Inches, the distance of the two beams of
Light, and the Diameter of the white Ring being 2-3/8 Inches.
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