288 GENERAL VIEWS ON ARCHEOLOGY. 



peculiar characteristic of the metal, that of occasionally containing 

 crystals of virgin silver, betrays its origin, and shows that it was 

 brought from the neighborhood of Lake Superior. This region is still 

 rich in metallic copper, of which single blocks attaining a weight of 

 fifty tons have lately been discovered. There was even found at the 

 bottom of an old mine a great mass of copper, which the ancients had 

 evidently been unable to raise, and which they had abandoned, after 

 having cut off the projecting parts with stone hatchets. 1 



The elate of this American age is unknown ; all we know is that it 

 must reach as far back as ten centuries at least, that space of time 

 being deemed necessary for the growth of the virgin forests, now 

 flourishing upon the remains of that antique civilization of which the 

 modern Indians have not even retained a tradition. 



It is finally worthy of remark that the "mound-builders," as the 

 Americans call the race of the Copper-age, seem to have preceded and 

 prepared the Mexican civilization, destroyed by the Spaniards; for in 

 progressing southwards, a gradual transition is noticed from the an- 

 cient earth-works of the Mississippi valley to the more modern con- 

 structions of Mexico, as found by Cortez. 



In Europe, the remains of a copper-age are wanting. Here and 

 there a solitary hatchet of pure copper is found; but this can easily be 

 accounted for by the greater frequency of copper, while tin had usually 

 to be brought from a greater distance, so that its supply was more 

 precarious. 



Europe did not witness the regular development of a copper-age. 

 It seems, according to M. Worsaac's very just remark, that the art of 

 manufacturing bronze was brought from another quarter of the world, 

 where it had been previously invented. It was most probably some 

 region in Asia, producing both copper and tin, where these two metals 

 were first brought into artificial communication, and where also traces 

 of a still earlier copper-age are likely to be found. 



An apparently serious objection might be started here, by raising the 

 question how mines could be worked without the aid of steel. This, 

 however, is sufficiently explained by the fact that the hardest rocks 

 can be easily managed by the agency of fire. By lighting a large fire 

 against a rock, the latter is rent and fissured, so as to facilitate con- 

 siderably its quarrying. This method was frequently employed when 

 wood was cheaper, and is even practiced in the present day in the 

 mines of the Kammelsberg, in Germany, where it facilitates the work- 

 ing of a rock of extreme hardness. 



That metal of dingy and sorry appearance, but more precious than 

 gold or the diamond — iron — at length appears, giving a wonderful 

 impulse to the progressive march of mankind, and characterizing the 

 third great phase in the development of European civilization, very 

 properly called the Iron-age. 



Our planet never yields iron in its metallic or virgin state, for 

 the simple reason that it is too liable to oxydation. But among the 



1 Lapham. "The Antiquities of Wisconsin." Smithsonian Contributions to Knowiedge, 

 p. 76, 1855. 



