operation upon its Texture, as we seem to know what it is, and as is immediately perform’d, and that several wayes without at all prejudicing the Body, or making any sensible alterations in its Manifest Qualities.  And I am the more willing to expose my hasty Tryals to Monsieur Zulichem, and to You, because, he being upon the Consideration of Dioptricks, so odd a Phaenomenon relateing to the Subject, as probably he treats of, Light will, I hope, excite a person to consider it, that is wont to consider things he treats of very well.  And for you Sir, I hope you will both recrute and perfect the Observations you receive, For you know that I cannot add to them, having a good while since restor’d to Mr. Clayton the Stone, which though it be now in the hands of a Prince that so highly deserves, by understanding them, the greatest Curiosities; yet he vouchsafes you that access to him as keeps me from doubting, you may easily obtain leave to make further Tryals with it, of such a Monarch as ours, that is not more inquisitive himself, than a favourer of them that are so.  I doubt not but these Notes will put you in mind of the Motion you made to the Society, to impose upon me the Task of bringing in, what I had on other occasions observ’d concerning shining Bodies.  But though I deny not, that I sometimes made observations about the Bolonian Stone, and try’d some Experiments about some other shining Bodies; Yet the same Reasons that reduc’d me then to be unwilling to receive ev’n their commands, must now be my Apology for not answering your Expectations, Namely the abstruse nature of Light, and my being already over-burden’d, and but too much kept imploy’d by the Urgency of the Press, as well as by more concerning and distracting Occasions.  But yet I will tell you some part of what I have met with in reference to the Stone, of which I send you an account.  Because I find on the one side, that a great many think it no Rarity upon a mistaken perswasion, that not only there are store of Carbuncles, of which this is one; but that all Diamonds and other Glistering Jewels shine in the Dark.  Whereas on the other side there are very Learn’d Men, who (plausibly enough) deny that there are any Carbuncles or shining Stones at all.

And certainly, those Judicious men have much more to say for themselves, than the others commonly Plead, and therefore did deservedly look upon Mr. Clayton’s Diamond as a great Rarity.  For not only Boetius de Boot, who is judg’d the best Author on this Subject, ascribes no such Virtue to Diamonds, but begins what he delivers of Carbuncles, with this passage.[26] Magna fama est Carbunculi.  Is vulgo putatur in tenebris Carbonis instar lucere; fortassis quia Pyropus seu Anthrax appellatus a veteribus fuit.  Verum hactenus nemo nunquam vere asserere ausus fuit, se gemmam noctu lucentem vidisse.  Garcias ab Horto proregis Indiae Medicus, refert se allocutum fuisse, qui se vidisse affirmarent.