There is no scientific way to trace or test either the precise nature or the exact degree of the influence on a people of their history. The impact varies from one particular individual or group to another, as does the very reading of historical facts themselves. Even a scholar inescapably reads the historical record in much the same way as he would look at a mirror--what is most clear to him is the image of his own values, his sense of his own identity. Yet, there persists in history the concept of national identity, and the transmission of that identity from generation to generation transcends even biological inheritance. The son of a Swedish immigrant in America has no particular trouble regarding Thomas Jefferson as a "forefather." The moments and the memories and the events of a nation's history implant themselves in the consciousness of each generation, and each generation, living its own life and creating its own identity, subtly changes the composition of the continuing stream of history.