MORLOT — SOME GENERAL VIEWS ON ARCHEOLOGY. 
51 
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 ancient earth- works of the Mississippi valley to the more modem 
constructions 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. Troyon'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 probable 
some region in Asia, producing both copper and tin, where these two 
metals were first brought into artificial combination, and where also 
traces of a still earher 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 facili- 
tate considerably its quarrying. This method was frequently 
employed when wood was cheaper, and is even practised in the pre- 
sent day in the mines of the Rammelsberg, in Germany, where it 
facilitates the working 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 produces iron in its metallic or virgin state, for 
the simple reason that it is too liable to oxydation. But among the 
aerolites there are some composed of pure iron, with a little nickel, 
which alters neither the appearance, nor the qualities of the metal. 
Thus the celebrated meteoric stone met with by PaUas in Siberia was 
