Gold Mines of Georgia. 11 



Sir H. Davy, since extended and modified by others,) some very com- 

 bustible substance, as potassium, sodium, or calcium, or some substance 

 powerfully attracting water, as quick lime, may predominate and to 

 which water may have percolated, or more probably have penetrated, 

 in consequence of the hydrostatic pressure of the ocean ; in either 

 case it would happen, that a violent eruption must take place, atten- 

 ded with all the phenomena of earthquakes and volcanoes; should 

 the exploding gas have sufficient force and meet with quartz in fu- 

 sion near the fissures, it would of course, force it into them, filling 

 them more or less, according to the supply of quartz, and the project- 

 ing force of the gas. The location of these supposed fires, seems to 

 be in a subterranean region, abounding with quartz and the materials 

 of granite, as they are the most frequent of the substances filling veins. 

 The granite contains the following metals, or substances having me- 

 tallic bases, sulphuret of molybdenum, lead, zinc, and copper; sul- 

 phate of lead and of barytes; magnetic iron and plumbago. I am 

 not aware, however, that the granites of Georgia, contain any of 

 these metals. It is a question of importance to the miner, how far 

 when working a vein, he should go with his excavations. 1 know of 

 no rule that would apply generally, for although mines have been 

 wrought in Chili and Peru, to the depth of nine hundred feet, yet as 

 we have no such description of the geological formations of those 

 countries as would answer the purpose of the miners, we are com- 

 pelled to suspend the exercise of our judgment, until we know that 

 analogous or equivalent circumstances, exist in the geological char- 

 acter of those countries, and of this. Gold is said to occur in " vast 

 quantities," at the depths, mentioned above. I think it advisable, 

 in experimental excavations, to follow the vein as long as we can per- 

 ceive a trace, or until we arrive at such depth, that it could not, though 

 tolerably rich be profitably worked. It is usual with us, to sink a 

 shaft on the vein and assay the quartz as we descend, and as soon as 

 we arrive at a rich place, to commence tunneling* and separating the 

 gold. It would, however, more surely lead to the attainment of the 

 knowledge so much needed, if the former course were pursued, and 

 the tunnel delayed until we were satisfied, that we had gone as deep 

 as is required. It is probable that rich mines "are, every day, aban- 

 doned, in consequence of disappointments in shafts of twenty, thirty, 



* I use the word tunnel, although the miner would probably express the stme 

 idea by the terra " gallery," as in Jacob's Inquiry. 



