REPORT OF THE SECRETARY. 37 



country, and hence it becomes an important object of inquiry to 

 determine whether any real types of the paUeolithic age exist in North 

 America. The two stone ages, however, are characterized by tlie 

 use of stone or bone, to the exclusion of metal. 



It is evident, from the specimens which have been collected, that 

 there was a period when bronze was extensively used for arms and 

 implements. This is particularly manifest in the examination of 

 tumuli, in which stone and bronze implements are found existing 

 together. Some of the bronze axes, in many cases, appear to be 

 mere copies of those of stone, as indeed is the iron axe used by the 

 pioneers in clearing the American forest. 



The bronze age is also distinguished from the stone age by the bones 

 of animals which are found mingled with the implements. Those 

 of wild beasts prevail in the former, while those of tame beasts are 

 most numerous in the latter. No articles of bronze have been found in 

 this country, though those of copper, showing a less advance in art, 

 are frequently found in ancient mounds. 



The iron age appeared when the metal was first used for weapons 

 and cutting instruments, and gradually extends into the twilight of his- 

 tory. From all the remains which have been found, it is evident that 

 neither bronze nor stone implements were used in northern Europe 

 at the commencement of the Christian era, and that the inhabitants 

 of these regions were not as low in the scale of civilization as the 

 accounts of their conquerors would seem to place them. 



Exchanges. — The system of international scientific and literary 

 exchanges, to facilitate the correspondence between learned institu- 

 tions and individuals of the Old and New World, has been fully main- 

 tained during the past year, 1, 083 boxes and packages having been 

 sent out, and 782 received since the date of the last report, most of 

 them with a large number of sub-parcels enclosed. 



These packages, as in former j^ears, contain the publications of 

 institutions, public documents, transactions of societies, scientific 

 works present(-d by individuals, specimens of natural history, eth- 

 nology, <fec. This part of the operations of the establishment has 

 found much favor with the public. " We have nothing of the kind," 

 says a recent English publication, "in this country, and the difficulty 

 in exchanging books and specimens is much felt. The comparative 

 cheapness of freight is more than made up by the complicated 

 agencies and other extra charges, which can scarcely be avoided even 

 by those initiated in the secrets of the business. The sending one 



