98 



compared by Mr. Rashleigh to the coating of an onion. 

 It is found from a light to a dark green ; the surface is some- 

 times tinged with, and passing into a red, or crimson. Its form 

 is generally in protuberating knobs or mammillae. Mala- 

 chites, though well known in many parts of England, have 

 been generally esteemed foreign productions : Dr. Babing- 

 ton, however, mentions the harder sort, resembling the 

 foreign, being found at Helstone, and the Land's End in 

 Cornwall, in the South of Wales and Yorkshire. We 

 have it from Wheal Unity, and many parts of Corn- 

 wall. The softer sort is not unfrequent among copper 

 ores, with the other which we have from North Wales, as 

 before mentioned \ and our friend, Dr. Ridout, was so good 

 as to give us a specimen which he gathered himself at Dod- 

 dington mine, in Somersetshire. They are said to contain 

 from 66 to 15 per cent, copper, 1 9*4 carbonic acid, and 

 5'6 water, and sometimes a little arsenic. Hardness, 5-7. 

 Kirw. Spec. Grav. 3'5 to 3*994. 



