翻译划线部分 Within the span of a hundred years , in the seventeenth and early eighteenth centuries , a tide of emigration -one of the great folk wanderings of history-swept from Europe to America. ( 46 ) This movement , driven by powerful and diverse motivations , built a nation out of a wilderness and , by its nature , shaped the character and destiny of an uncharted continent. ( 47 ) The United States is the product of two principal forces-the immigration of European peoples with their varied ideas , customs , and national characteristics and the impact of a new country which modified these traits. Of necessity , colonial America was a projection of Europe. Across the Atlantic came successive groups of Englishmen , Frenchmen , Germans , Scots , Irishmen , Dutchmen , Swedes , and many others who attempted to transplant their habits and traditions to the new world. ( 48 ) But , the force of geographic conditions peculiar to America , the interplay of the varied national groups upon one another , and the sheer difficulty of maintaining old-world ways in a raw , new continent caused significant changes. These changes were gradual and at first scarcely visible. But the result was a new social pattern which , although it resembled European society in many ways , had a character that was distinctly American. ( 49 ) The first shiploads of immigrants bound for the territory which is now the United States crossed the Atlantic more than a hundred years after the fifteenth- and sixteenth-century explorations of North America. In the meantime , thriving Spanish colonies had been established in Mexico , the West Indies , and South America. These travelers to North America came in small , unmercifully overcrowded craft. During their six- to twelve-week voyage , they subsisted on meager rations. Many of the ships were lost in storms , many passengers died of disease , and infants rarely survived the journey. Sometimes tempests blew the vessels far off their course , and often calm brought interminable delay. To the anxious travelers the sight of the American shore brought almost inexpressible relief. Said one chronicler , “ The air at twelve leagues' distance smelt as sweet as a new-blown garden.” The colonists' first glimpse of the new land was a vista of dense woods. ( 50 ) The virgin forest with its richness and variety of trees was a real treasure-house which extended from Maine all the way down to Georgia in the south. Here was abundant fuel and lumber. Here was the raw material of houses and furniture , ships and potash , dyes and naval stores.