Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/92

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Galena is the only lead ore procured in abundance from the veins of this formation; but the white and steel grained ore are occasionally discovered. Silver is contained in the ore in different. proportions, varying from 2 to 42 ounces in the fother of 21 cwts.; but 12 ounces may be considered as the general average. If 7 or 8 ounces can be extracted the lead is worth refining; though this must in some measure depend on the prices of silver and of refined lead when compared with that of common lead.[1] If the galena is good in quality 4 bings or 32 cwts. of clean ore will yield 20 cwts. of lead; but 4 bings or 34 cwts. are generally required to produce that weight of metal.

The following is the quantity of lead shipped at the port of Newcastle; average for 6 years previous to

1776 per annum 7072 tons.
In 1804 10352
1805 9162
1806 3911
1807 6809
1808 8155
1809 4972 = 71041 pieces
1810 5670
1811 4553 = 68940.
1813 = 97940
  1. Price of Common Lead. April 1814. £30 per fother of 21 cwts.
    of Refined lead 31 ditto
    of Fine Silver 7s. 5d. per oz.
    N.B. The fother on the Tyne is 21 cwts. On the Tees 22 cwts.