358 Analysis of Scientific Books and Memoirs, 



cohesion, when pressure to experiments on this strain, and when trans- 

 verse strains are to be resisted to experiments on the transverse strength. 

 There is, therefore, in these cases, no question concerning the relative re- 

 sistance to compression, extension, neutral ones, &c. <U the same time, the 

 other inquiry is highly interesting, and being now fairly before the pub- 

 lic, it will, we have little doubt, meet with the attention it merits, from 

 such of our readers as are conversant or interested in the physical theory 

 of the strength of materials. 



II. On the Gold Mines of North Carolina. By Denison Olmsted, 

 Professor of Chemistry and Mineralogy in the University of North 

 Carolina. 



1 his very interesting paper, which we are desirous of laying before our 

 readers, has been published in America in Professor Silliman's Journal. 

 The description of the mines themselves is too valuable to admit of any 

 abridgement. 



The gold mines of North Carolina, which have recently become an ob- 

 ject of much inquiry both at home and abroad, are situated between the 

 35th and 36th degrees of N- latitude, and between the 80th and 81st de- 

 grees of W. longitude from London. They are on the southern side of 

 the State, not far from the borders of South Carolina, and somewhat west- 

 ward of the centre. Through the gold country flows the river Pedee, re- 

 ceiving, within the same district, the Uwharre from the north, and Rocky 

 river from the south, both considerable streams- Above the junction with 

 the Uwharre, the Pedee bears the name of Yadkin. 



The gold country is spread over a space of not less than 1000 square 

 miles. With a map of North Carolina one may easily trace its bounda- 

 ries, so far as they have been hitherto observed. From a point taken eight 

 miles west by south of the mouth of the Uwharre, with a radius of eighteen 

 miles, describe a circle, — it will include the greatest part of the county of 

 Montgomery, the northern part of Anson, the north-eastern corner of Mu- 

 lenberg, Cabarrus, a little beyond Concord on the west, and a corner of 

 Rowan and of Randolph- In almost any part of this region, gold may be 

 found, in greater or less abundance, at or near the surface of the ground. 

 Its true bed, however, is a thin stratum of gravel inclosed in a dense mud, 

 usually of a pale blue, but sometimes of a yellow colour. On ground that 

 is elevated and exposed to be washed by rains, this stratum frequently 

 appears at the surface ; and in low grounds, where the alluvial earth has 

 been accumulated by the same agent, it is found to the depth of eight feet : 

 where no cause operates to alter its original depth, it lies about three 

 feet below the surface- Rocky river and its small tributaries which cut 

 through this stratum, have hitherto proved the most fruitful localities of 

 the precious metal. 



The prevailing rock in the gold country is Argillite. This belongs to 

 an extensive formation of the same, which crosses the State in numerous 

 beds, forming a zone more than twenty miles in width, and embracing, 

 among many less important varieties of slate, several extensive beds of 



