275 



4thly. That charcoal is not an oxide of carbon ; since, when rightly 

 prepared, it requires quite as much oxygen for its combustion as 

 diamond. 



And lastly, That the diamond differs from charcoal, solely in the 

 firmness of its aggregation, which is generally known to be an ob- 

 stacle to every chemical change. 



An Account of the Relistian Tin Mine. By Mr. Joseph Carne, in a 

 Letter to Davies Giddy, Esq. M.P. F.R.S. Read May 7, 1807. 

 [Phil. Trans. 1807, p. 293.] 



Mr. Davies Giddy communicated a letter from Mr. Joseph Carne, 

 giving an account of the Relistian Mine in Cornwall, in which 

 rounded pebbles were found at the depth of seventy-five fathoms 

 from the surface. The description is accompanied with a section of 

 the mine, and plan of the lode. 



The lode has been seen at various depths, from twelve to ninety 

 fathoms, but its width then diminishes rapidly toward the east, but 

 more gradually toward the west. The substances not metallic are 

 schist, chlorite, and quartz. There is an engine-shaft at eight fathoms 

 from the lode, on the north side from which levels are driven to the 

 lode in the direction of a flucan, or cross lode, which cut the main 

 lode nearly at 45 from N.W. to S.E. The distance, in this oblique 

 direction, is about fifteen fathoms ; for the first ten fathoms there 

 was only one flucan, of four inches width. Then it became divided 

 into four parts, so much divergent from each other, that at the depth 

 of seventy-five fathoms the extreme branches extended twelve feet 

 in width ; where the flucan reached the lode at this depth, there was 

 first discovered a little copper, and then a body of pebbles, the section 

 of which was about twelve feet square. In this part of the lode the 

 schist greatly predominates ; of course (says Mr. Carne) the pebbles 

 are schistose, cemented in some parts by chlorite, in others by oxide 

 of tin, which is generally crystallized, and in some of the crevices 

 there is a little copper pyrites. The pebbles did pot continue in a 

 body to the height of more than two fathoms ; but scattered bunches 

 were found four fathoms above, and six fathoms below the place 

 where they were first discovered. 



At the depth of sixty-five fathoms, and in the lode adjacent to the 

 flucan, on each side, had been found also a great number of schistose 

 stones ; but these were angular fragments, not rounded ; nor was 

 there any tin in or about them. 



An Analysis of the Waters of the Dead Sea and the River Jordan. By 

 Alexander Marcet, M.D. one of the Physicians to Guy's Hospital. 

 Communicated by Smithson Tennant, Esq. F.R.S. Read June 18, 

 1807. [Phil. Trans. 1807, p. 296.] 



This analysis is preceded by a short abstract of the notice taken 

 of the Dead Sea by various ancient authors, by Strabo, by Tacitus, 



T2 



