20 



when dry. — Common Opal is nearly the same in appearance, 

 either wet or dry, and comprises the grayish, blueish, green- 

 ish, and yellowish parts with a milky or waxy lustre, (like the 

 Semi- or Halb-Opal of Werner,) with a vitrescent effulgence 

 or yellowish fiery glare, in some lights, especially in the 

 flaws. Fracture glassy. Hardness sufficient to cut glass. 



The most beautiful specimen ever discovered of this sub- 

 stance is in the possession of J. M. Cripps, Esq. of Lewes, 

 in Sussex. It was presented to that gentleman at Constan- 

 tinople, by his excellency Count Ludolf, envoy from the 

 court of Naples to the Porte. It belonged originally to the 

 Capudan Pacha, and was found in Bulgaria. Unlike the 

 common specimens, in which Opaline Wood appears in 

 small veins intersecting the common Fossil Wood, or in a 

 fragile state like Pitch Stone, it has throughout the whiteness 

 of Cacholong, and in some parts the lustre and colour of the 

 genuine Opal. It is larger than a man's body, and weighs 

 148 lb. 9-f- oz. avoirdupois. It presents half the trunk of a 

 large trfce, with the node of one of its principal branches. 

 The timber, the bark, and every part of the mass is perfectly 

 opaline. 



The Right Honourable Sir Joseph Banks had a Mammoth's 

 grinder in his possession, lately found on our coast, opalized. 

 Other bones of the Mammoth are found in this country 

 occasionally. I saw a tooth of a Mammoth from America, 

 somewhat opalized, in the late Mr. John Hunter's mu- 

 seum. There are some also in the British Museum. 



Sir Hans Sloane gave 2001. for an Ocidus mundi now in 

 the British Museum. 



