TAB. CCCI. 



CUPRUM sulphureum. 

 Sulphur et of Copper ; Swimming Pyrites. 



Div. 2. Imitative. 



It is now no novelty to find Metals of very light specific 

 gravity, since Mr. Davy's discovery of Sodium and Potassium, 

 yet we have no account of Swimming Copper Pyrites, that 

 I know of. I am therefore glad to treat the world with 

 this novelty. Some time ago Mr. Carne favoured me with 

 the Swimming Quartz which had some porous Sulphuret 

 and Oxide of Copper about it, which gave me reason to 

 suppose some Swimming Copper Ore might be found, 

 since which time he has kindly informed me that he has 

 procured a specimen, and I have, by chance, received this 

 from the same place *. 



It would seem from its appearance to have been formed by 

 passing among the irregular interstices of some shattered 

 part of a rock which is completely gone in the same manner 

 as from the Quartz above. It is in somewhat plated 

 chambers irregularly angular of various dimensions. It is 

 extremely friable, and the tenuity of the plates or divisions 

 will scarcely allow of its being handled. It is a kind of 

 exception to the rule by which we judge of the specific 

 gravity or weight of Metals by the hand, to distinguish 

 them from the Combustibles and Earths, and is a good 

 example of an argument regarding the gravitating principle^ 



* From Trelistian Mine, near Penzance in Cornwall, 

 VOL. IV. J3 



