182L] Scientific Intelligence, 39^, 



In Six Months endins: Dec. 1S20. 



The produce of 72 mines 3962 tons, of which, 1891 tonsv/ere pro* - 

 duced by six mines as under: 



Ore. Copper. 



United mines 5594 tons 481 tons 



Dolcoath 5665 403 j 



Wheal Abraham, &c. . . 5069 388 



Treskerby 2199 213 



Wheal Drevvollas. ..... 2074 205 



Pembroke 2612 201 



23213 1891 



Produce of the ore about 8i per cent. 

 Price of copper, 113/. lO^. per ton. 



General Return of Copper raised in England and Ireland, 



One Year ending June {S\9. 



Tons. Cwt. Qrs. 



Cornwall 6974 2 2 



Anglesea 564 



Devon 433 



Ireland, Ecton, and other 

 mines in StaiFordshire 

 and elsewhere* 596 10 3 



8567 13 1 

 One Year ending June 1820. 

 Tons. 



Cornwall 6915 



Anglesea 561 



Devon 414 



Ireland, Ecton, and other 



mines in StaiFordshire 



and elsewhere* 813 11 



8703 15 2 



III. Native Hydrate of Magnesia. 



The native hydrate of magnesia was first discovered, and ranked a» 

 a separate mineral, by the Jate Dr. Bruce, of New York. It was found 

 only atHoboken, in New Jersey, traversing serpentine in all directions 

 in veins of from a few lines to two inches in thickness. 



Dr. Hibbert found this substance in 1817 at Swinaness, in Unst, one 

 of the Shetland Isles, traversing serpentine in all directions, being 

 mixed with the magnesian carbonate of lime, and forming veins from 

 half an inch to six or eight inches broad. 



Chemical Character. — Hydrate of magnesia dissolves entirely in 



• Part of this quantity is from Cornwall; but from the mode of sale, no exact division 

 can be made. 



