XX1V 
proportions of tin and of copper obtained by the smelter from 
crude vein-stone extracted by the miner were respectively -esti- 
mated in ; 
1778, proportion of tin in ore 0-020381* proportion of copper in ore 0-020000* 
1862, 5 0:013000+4+ ” 0:0212504§ 
1869, the ores of the most productive tin-mine afforded ...... 0:013000,+|| 
their weight of metal.q It is a remarkable fact that in all dodes, 
whatever may be the nature of their produce, the parts most 
highly inclined are always the most productive.** Most bodies 
(courses), as well of tin, as of copper-ore have within their respec- 
tive lodes an endlong dip or shooi,tt which usually approximates 
* Pryce, Mineral: Cornub: p. 186. 
+ Moissenet, Annales des Mines, 6me Série, i1., p. 252. 
+ The tin-ore of Cornwall affords on an average (13 parts in 20) 0.650000 
its weight of metal. 
gs The mean percentage of metal obtained from the copper-ores of 
Cornwall is (64) 0:061250 its weight. Hunt, Mining Statistics, 1857-1867. 
|| Thomas, Journal of the Royal Institution of Cornwall, ii1., p. 198. 
q On the southern shore of Lake Superior—the vein-stones of— 
The Northwest mine afforded .. 0:013600 their weight of native copper, 
Clift 96 y»- «- 0:163000 53 ins 
Waurrtney, Metallic Wealth of the United States, p. 271. 
Dg Henwoop, Cornwall Geol: Trans: viil., p. 485. 
At Chanarcillo in Chili the vein-stones of the Colorada mine during 1855- 
1856 yielded from 0-012964 to 0:012966 their weight of silver. 
Henwoop, Cornwall Geol: Trans: viii., p. 97. 
In North Wales, the vein-stones at Clogau yielded from 0-000002 to 
0:045765 and averaged 0:000048 their weight of gold. 
Henwoon, Cornwall Geol: Trans: viii., p. 641. Table xxii. 
At Berezovsk in the Ural the vein-stones wrought from 1745 to 1841 
yielded on an average 9.000013 their weight of gold. : 
Mourcuison, Dr Vernevit and Von Keysurtine, Russia in Hurope, i., p. 476. 
Their weight of Gold. 
In Nova Scotia, various vein-stones yielded from 0:000025 to 0-000032 
>, Virginia, 6 5 » 0°000005 ,, 0:035659 
», Brazil, the vein-stones of Catta Branca ,, 0:000007 ,, 0:000019 
in - Morro Velho’ ,, 0:000010 ,, 0:000036 
i ‘ Agoa Quente  ,, 0:000001 ,, 0-016988 
& An Don Pedro », 0:000008 ., 0:002364 
a - Gongo Soco »,  0:000001 ,, 0:521173 
Henwoop, Cornwall Geol: Trans: viii., pp. 179-384. Table xxii. 
++ Thomas, Report, p. 20. Henwood, Hdin: New Phil: Journal, xxii., 
p. 158; Cornwall Geol: Trans: v., p. 231; viil., p. 705. Fox, Reports of the 
Royal Corn: Pol: Society, iv., p. 87. Burr, Mining Review, ii., p. 169. 
De la Beche, Report, p. 324. 
++ Henwood, Hdin: New Phil: Journal, xxii., p. 157; Cornwall Geol: 
Trans: v., p. 193. Fox, Reports of the Royal Corn: Pol: Society, iv., p. 95. 
De la Beche, Report, p. 336. 
