On Gems. igg 



it, Mushet converted the Iron into tlie same state without 

 the diamond being present. Mackenzie supports Guyton, 

 and denies that tliis could have been done without the pre- 

 sence of some carbonaceous matter in the crucibles. Mushet 

 says that carbon penetrates the crucibles at these elevated 

 temperatures : and thus the experiment rests. 



The substance of diamonds is lamellated, consisting of 

 very thin plates like those of talc, but extremely hard and 

 intimately united, whose direction lapidaries umst find out, 

 not only to cleave the ill-shaped stones, but to cut and shape 

 them properly. This last operation is performed by rub- 

 bing one diamond with another till it has acquired the 

 shape ; it is afterwards polished on a horizontal wheel of 

 steel, employing the same powder that falls from their rub- 

 bings with common olive oil. 



Jeffries calculates the mean value of diamonds by multi- 

 plying the square of their weight in carats by two pounds 

 sterling, when the diamond is rough or uncut ; but if it is 

 already cut, the simple square of their weight must be mul- 

 tiplied by eight pounds sterling : this great difference in 

 price proceeds from the great loss which a diamond suffers 

 ni being cut. 



The two first of the following diamonds are uncut, the 

 other six are cut diamonds : 



1st. The greatest diamond that ever was known in the 

 world is one belonging to the king of Portugal, which wai? 

 found in Brasil ; it is still uncut : it was of a larger size, 

 but a piece v.-as cleaved or broken off by the ignorant coun- 

 tryman who chanced to find this great gem, and tried its 

 hardnej;s by the stroke of a large hammer on an anvil. 



This prodigious diamond weighs 1680 carats ; if we em- 

 ploy to value it the general rule above mentioned, this great 

 gem must be worth at least 5,614,800 pounds sterling, 

 which are the product of 1680^ by two pounds. 



2d. The diamond which adorns the imperial sceptre of 

 Russia, under the eagle at the top of it, weighs 779 carats, 

 and is worth at least 4.654,728 pounds sterling, although 

 it hardly cost 135,417 guineas. This diamond was one "of 

 the eyes of a Malabarian idol, named Scheringham. A 

 French grenadier, who had deserted from the Iiidian ser- 

 vice, contrived so well as to become one of the priests of 

 that idol, from which he had the opportunity to steal its 

 eye: he ran away to the English at Tricinapalli, and 

 tliencc to Madras. A ship captain bought it of him for 

 2(),()()() rupees ; afterward a .Jew gave 18,000 pounds ster- 

 ling for it : at last a Greek merchant, named Gregory Suf- 

 N 4 fras. 



