Being look’d on in the Day time, though in a Bed, whose Curtains were carefully drawn, I could not discern it to Shine at all, though well Rubb’d, but about a little after Sun-set, whilst the Twilight yet lasted, Nay, this Morning[37] a pretty while after Sun-rising, (but before I had been abroad in the more freely inlightned Air of the Chamber) I could upon a light Affriction easily perceive the Stone to Shine.

[35] These were brought in and Read before the Royal Society, (the Day
following) Oct. 28. 1663.

[36] The Stone it self being to be shown to the Royal Society, when the Observations were deliver’d, I was willing (being in haste) to omit the Description of it, which is in short, That it was a Flat or Table Diamond, of about a third part of an Inch in length, and somewhat less in breadth, that it was a Dull Stone, and of a very bad Water, having in the Day time very little of the Vividness of ev’n ordinary Diamonds, and being Blemished with a whitish Cloud about the middle of it, which covered near a third part of the Stone.

[37] Hast made me forget to take notice that I went abroad the same Morning, the Sun shining forth clear enough, to look upon the Diamond though a Microscope, that I might try whether by that Magnifying Glass any thing of peculiar could be discern’d in the Texture of the Stone, and especially of the whitish Cloud that possest a good part of it.  But for all my attention I could not discover any peculiarity worth mentioning.

Secondly, The Candles being removed, I could not in a Dark place discern the Stone to have any Light, when I looked on it, without having Rubb’d or otherwise prepar’d it.

Thirdly, By two white Pibbles though hard Rubb’d one against another, nor by the long and vehement Affriction of Rock Crystal against a piece of Red cloath, nor yet by Rubbing two Diamonds set in Ring, as I had Rubb’d this Stone, I could produce any sensible degree of Light.

Fourthly, I found this Diamond hard enough, not only to enable me to write readily with it upon Glass, but to Grave on Rock Crystal it self.

Fifthly, I found this to have like other Diamonds, an Electrical faculty.[38]

  [38] V. For it drew light Bodies like Amber, Jet, and other Concretes
  that are noted to do so; But its attractive power seem’d inferiour to
  theirs.

Sixthly, Being rubb’d upon my Cloaths, as is usual for the exciting of Amber, Wax, and other Electrical Bodies, it did in the Dark manifestly shine like Rotten Wood, or the Scales of Whitings, or other putrified Fish.

Seventhly, But this Conspicuousness was Fainter than that of the Scales, and Slabber (if I may so call it) of Whitings, and much Fainter than the Light of a Glow-worm, by which I have been sometimes able to Read a short Word, whereas after an ordinary Affriction of this Diamond I was not able to discern distinctly by the Light of it any of the nearest Bodies:  And this Glimmering also did very manifestly and considerably Decay presently upon the ceasing of the Affriction, though the Stone continued Visible some while after.