82 Mr. N. J. Winch on the Geology of 



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 7j 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.* 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 

 1807 

 1808 

 1809 

 1810 

 1811 

 1813 



3911 

 6809 

 8155 



4972 = 71041 pieces 

 5670 



4553 = 68940 

 97940 



was constructed about forty years ago by the late Mr. Westgarth, agent to Sir Thomas 

 Blackett, and the following data taken on the spot will shew its power. 



Column that works the Engine 20 fathoms 



Diameter of the Piston 7 inches 



Length of the Stroke 5 feet 



Diameter of the bucket that lifts the water 6 inches 



Length of the column to be lifted 19 fathoms 



Number of strokes per minute 8 or 10 



* 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 cwtt. 



