American philosopher and statesman Thomas Jefferson (1743-1826) was the third president of the United States. A man of broad interests and activity, he exerted an immense influence on the political and intellectual life of the new nation.

Thomas Jefferson was born at Shadwell, Va., on April 13, 1743. His father had been among the earliest settlers in this wilderness country, and his position of leadership descended to his eldest son, together with 5,000 acres of land.

Jefferson became one of the best-educated Americans of his time. At the age of 17 he entered the College of William and Mary, where he got exciting first glimpses of "the expansion of science, and of the system of things in which we are placed." Nature destined him to be a scientist, he often said; but there was no opportunity for a scientific career in Virginia, and he took the path of the law, studying it...