ON" THE HYPOTHESIS OF EVOLUTION. 151 



tin, forming bronze and brass, was discovered and used in Enrojie, 

 while that with silver appears to have been most readily produced 

 in America, and was consequently used by the Peruvians and other 

 nations. 



The discovery of the modes of reducing iron ores placed in 

 the hands of man the best material for bringing to a shape 

 convenient for his needs the raw material of the world. All im- 

 provements in this direction made since that time have been in 

 the quality of iron itself, and not through the introduction of any 

 new metal. 



The prevalent phenomena of any given period are those which 

 give it its character, and by which we distinguish it. But this 

 fact does not exclude the co-existence of other phenomena belong- 

 ing to prior or subsequent stages. Thus during the many stages 

 of human progress there have been men more or less in advance 

 of the general body, and their characteristics have given a pecul- 

 iar stamp to the later and higher condition of the whole. It 

 furnishes no objection to this view that we find, as might have 

 been anticijoated, the stone, bronze, and iron periods overlapping 

 one another, or men of an inferior culture supplanting in some 

 cases a superior people. A case of this kind is seen in North 

 America, where the existing *^ Indians," stone-men, have suc- 

 ceeded the mound-builders, copper-men. The successional rela- 

 tion of discoveries is all that it is necessary to prove, and this 

 seems to be established. 



The period at which the use of metallic implements was intro- 

 duced is unknown, but Whitney says that the language of the 

 Aryans, the ancestors of all the modern Indo-Europeans, indicates 

 an acquaintance with such implements, though it is not certain 

 whether those of iron are to be included. The dispersion of the 

 daughter races, the Hindoos, the Pelasgi, Teutons, Celts, etc., 

 could not, it is thought, have taken j^lace later than 3000 b. c. — 

 a date seven hundred years prior to that assigned by the old chro- 

 nology to the Deluge. Those races co-existed with the Egyptian 

 and Chinese nations, already civilized, and as distinct from each 

 other in feature as they are now. 



Improvement in Architecture. — The earliest periods, then, were 

 characterized by the utmost simplicity of invention and construc- 

 tion. Later, the efforts for defense from enemies and for architect- 

 ural display, which have always employed so much time and 

 power, began to be made. The megalithic period has left traces 



