The works of the Honourable Robert Boyle, Esq., epitomiz'd by Richard Boulton ... ; illustrated with copper plates.

CHAP. XXIII. Observations of a Diamond that shines in the dark.

* 1.1HAving met with a Diamond, which, tho' it would not yield light in the day, would afford a conspicuous light in the Night, I thought it would be of no small use in explain∣ing the abstruse Nature of Light. And tho' a great many think it no rarity, that there are Carbuncles and Diamonds which shine in the dark, yet there are some who deny, that there are any shining stones at all, as Boetius de Boot; Johannes de Laet, and Olaus Wormius, yet Va∣temannus and Garcias ab Horto, pretend to be Eye witnesses of Carbuncles which shone in the dark; and Marcus Paulus Venetus tells us, that the King of Zeilan had a Rubie as thick as a Man's arm, and a Palm long. And two Russian Cossacks tell us, that they heard from the People of Cottay, that their King had a Rubie which would shine Night and Day. And Benvonuto Cellini, an Italian Writer, gives us an account of a Carbuncle which affor∣ded a considerable Light in the Night. And we our selves have been informed of a shining substance found in Scotland.

And I am further told, that a Dutch Admiral had a Diamond, which when he opened a Coffer under Deck in a dark Room, would shine by its native Light, which is the more strange, be∣cause that is a much colder Climate than the East-Indies; for it is observable, that warmth

much contributes to the shining of such stones, since rubbing will cause some to shine, which when cold will not; which makes me the less doubt of what is said of right Turquois, viz. That it changes colour as the wearer is sick or well, and loses its splendor after Death, which is attested by the Observations of Boetius de Boot, and Olaus Wormius; and tho' Antonio N••ri tells us, that a Turquois discoloured and grown white, will regain its colour, if immersed in Oyl of sweet Almonds, yet Wormius tells us, that a Nephritick stone being dipped in a De∣coction of herbs lost its virtue. And it is ob∣served, that the Texture of Oculus Mundi will be so changed by being left in Water, that from Opacous it will become Transparent, which acquired lustre it will soon lose in the Air.

Observations made on Mr. Clayton's Diamond.

It was a flat Table Diamond ⅓ of an Inch long, and less in breadth, of a bad Water, and less vivid in the day than other Diamonds, being blemished with a whitish Cloud about the middle of it, which blemish covered near a third part of the stone.

This Diamond being looked upon in a shady place in the day, and also with a Microscope, neither any thing peculiar in the stone, nor a∣ny light was perceived.

Secondly, when the Candle was removed in a dark Room, it did not shine without be∣ing rubbed or otherwise prepared.

Thirdly, I could neither produce Light by rubbing together two Pebbles, nor by a vehe∣ment attrition of Rock-Crystal, nor by two Diamonds, as by this stone.

Fourthly, it was hard enough to grave upon Rock-Chrystal with it, and was endewed with an Electricity.

Fifthly, by rubbing it in the dark, it would be excited to shine like rotten wood, but much fainter than the scales or slabber of a Whiting, or than Glow-worms; and it presently ceased after the attrition was ended. But being rub∣bed brisksly it would continue its Light much longer, so that it lasted eight times as long as it was a rubbing▪

Sixthly, holding it near a faint fire excited its Luciferous Qualities a little, but by holding it near a Candle it was more apparently excited in a dark Room; and it acquired a little glimmer∣ing by being held near a red piece of Iron, as also by being contiguous to my naked Body sometime.

Seventhly, by being rubbed till it acquired Luciferous Qualities, it was also Electrical, but not when it was excited to shine by the Heat of the Fire or a Candle.

Eighthly, attrition varied its Luciferous Qua∣lities, as the Cloath varied in colour; but on white and red it succeeded best. It was like∣wise excited in some measure by being rubbed upon a white wooden Box; and a purely glazed Earth, which excited it much better than any other Body except white ones.

Ninthly, when it was excited, being plunged into Water, Spirit of Wine, Oyls of all sorts,

Acid Spirits, and Alkalizate Solutions, none of them destroyed its shining properties, but when it was taken out of the Water it was not so easily excited as before.

Tenthly, neither Spittle nor warm Liquors would extinguish its Light; but being rubbed with a transparent horn, I could discover Light through it, and sometimes little sparks of fire.

Eleventhly, being rubbed upon a blue Glass, the faint Light was not visible through it, but being first excited and then applyed to the Glass, the Rays were tinged in their passage through it.

Twelfthly, by pressing it hard upon a piece of white Tyle it became Luminous, as also it discovered a short Coruscation when I pressed my finger upon it: And if I thrust or stuck the point of a Bodkin against it, it would discover a short, but not a lasting Coruscation, so that its Light seemed to be promoted by pressure ra∣ther than attrition.

The same Experiments being tryed with o∣ther precious Stones, some Diamonds would by attrition be brought to a glimmering Light, but others would not; but neither the other precious Stones, nor Artificial or Natural Chrystal would afford the least glimmering of Light.

Notes

• * 1.1

  Observati∣ons on Di∣amonds.