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[Assembly 
practical miner of essential and indispensable importance in form- 
ing a correct judgment of the mode of working. The knowledge 
to be derived from well established data respecting the arrange- 
ment and distribution of mineral substances, is evident from many 
facts which can be adduced. 
For some years lime was exported from Britain to New South 
Wales, where native limestone exists in abundance. This could 
only have resulted from ignorance of the geological character of 
the country. 
In Cornwall, until recently, ores of silver and cobalt have been 
thrown away from a mine which, since the discovery of their va- 
lue, have yielded more than £10,000 per annum. The tin mines 
of Cornwall have been celebrated from the earliest periods of his- 
tory, but only within the last century have its copper ores been 
considered of any value, being previously used for mending the 
roads. Even at the present time little attention is paid to any 
thing except what is known to yield tin or copper. 
In Derbyshire, for many centuries, lead has been smelted from 
the common blue ore, yet the other ores of the same metal were 
used for mending roads or left in heaps as rubbish; these rejected 
ores have since been worked to good account, and even the mate- 
rials of a public road have been converted into metal. 
In North Carolina a gentleman had worked an ore of gold which 
yielded about $40 per ton; on examination the ore proved to be 
copper pyrites of good quality, and worth $100 per ton. In another 
case an ore of gold which yielded, by amalgamation, little more 
than $2 per bushel, gave on analysis more than $S0 per bushel.* 
Many instances might be mentioned of persons, in various parts 
of the country, who, believing that their estates contained valu- 
able veins of metallic ores, or beds of coal, have been induced to 
carry on expensive workings, in many cases, where they could ill 
afford the means. Excavations have been made to a considerable 
depth in solid rock, without the slightest appearance of metal, in 
belief that the vein lay below, and that it was necessary to remove 
the superincumbent rock before the ore would be found. In the 
greater number of such cases, a slight knowledge of geology would 
have shown that, in all probability, the result would prove un- 
* For the facts in relation to the gold ore, I am indebted to Mr. W. W. Mather. 
