An Account of Certain Transparent Pebles, Mostly of the Shape of the Ombriae or Brontiae: Wherefore I Have Called Them Brontiae Laeves, Pellucidae, Resplendentes, Adamantum Aemulae

II. An Account of certain transparent Pebbles, mostly of the shape of the Ombriae or Brontiae: Wherefore I have called them Brontiae Læves, Pellucidæ, Resplendentes, Adamantum Æmulæ. The Figures are taken from certain very clear and transparent Stones found in England, of a constant Shape. They are called in some ancient Leases of Royal Mines Rough or Mineral Pearl. They understanding, as I guess, by the Word Pearl, any thing that was resplendent and bright, and particularly figured like a Drop of Water, which these Stones have of themselves naturally, and without any Artifice; some of them being exactly Spherical, others like a Half Globe, others like a Half Oval, with an edge raised on the top: And in these general Figures great Varieties are to be observed. As for the Esteem the Ancients had of them, it was not without Reason; for besides that, their natural Figure and Beauty, where they have been well preserved, is commendable. Their Natural Polish is moreover not to be counterfeited, but very easy to be distinguish'd by a Microscope, from the Artificial Polish of Glass and Crystals. Now Gold, Silver, Diamonds and Pearl are for no other reason estimable, but because they have certain indelible Characters, which all the Subtilty and Wit of Man hath not yet been able to Counterfeit, notwithstanding the many Pretences thereunto. As Gold, for Example, for that it will endure the drowning in Antimony; Silver, that it abides the Test of Lead; Diamonds, for that of themselves, even without a Foil, they cast a Lustre. Cristalli quaedam, sive Echinite pellucidij Anglicani ex Silicetum genere, vel Sphericis, vel ad Dimidiatam Sphaeram aliquando accidentes. Lustre. Pearl is valued because of its Figures and peculiar Brightness not to be imitated. These Stones are of the Pebble kind, that is, not to be calcin'd by simple Fire; whereas most other figured Stones are calcinable with a very easy Fire. These Stones are, as I said, naturally polish'd and very hard and solid, and do not consist within of Laminæ or Flakes, but brake every way with great Difficulty, and naturally throughout smooth. As for their Figure, it comes nearest that of the Ombriæ; and many of them are very Ombriæ in shape. Other transparent Ombriæ I have seen, which yet are either very Flints, or of a flaky and soft Contexture, of the nature of Selenites; and such are to be found about Filobriggs, a noted Set of Rocks near Scarborough. As these Stones are of a very different Nature and Texture from all other Ombriæ I ever yet saw, and having no Vestigia of any Spinae in any part of them, I may reasonably enough conclude them to be Stones of their own kind: And they are in shape like some of the Ombriæ, yet for the Reasons above-said, they will not come, I think, within the suspicion of having been Animal Substances. For the rest, I am not averse to think, after so manifest and considerable Discoveries of this kind, as Auguftino Scilla had made in Sicily, that most of the Ombriæ have been Echini; and yet some of the Prickled, which Naturalists have hitherto called Lapides Judaici, may have belonged to some of those Ombriæ. But I perswade myself it will never be found, that any of them have ever belonged to any of the Stones in the present Table. I shall conclude with one Remark, and that is, to incite the Industry of the Curious, to a more narrow search into these matters. There are but two or three Echini yet discover'd, either in ours or the Mediterranean Sea. Sea. But of the Ombriae of Europe, besides these present Anomalous Stones, there are at the least Twenty Species figur'd and describ'd by Aldrovandus, Angustino Scilla, Dr. Plot, &c. and in vast quantities in most Counties of England: And I doubt not many more Species will yet be found out. All which are to be accounted for; as to the natural places, in what Seas they are to be found at this day. And if not in the European, as I think they will not, how and whence they came hither into this Island in such Plenty. But enough of this. Yours, &c.