Lewis Evans, born in Wales, is first on record in North America in 1736 when he bought an arithmetic book at Benjamin Franklin's bookstore in Philadelphia. He aided Franklin in his business and made the acquaintance of men such as Thomas Godfrey (1704-1749) of octant fame, James Logan (1674-1751), the botanist John Bartram (1699-1777), the Indian agent Conrad Weiser (1696-1760) and other mathematically and scientifically inclined men. Unlike in England where land boundaries had been surveyed (and fought over) for centuries, the North American continent presented vast stretches of land in the hands of native Americans whose social organization and concepts of land usage were antithetical to Europeans. The land, which was bought, traded, developed, deeded, or outright stolen from the Indians required surveying and mapping, crafts well developed in England. Colonies had their surveyor-generals from the outset. Mapping of the new world advanced from basically sea charts and coastal features to depiction of settled areas, often along rivers. Lewis Evans has been called the greatest of the 18th century cartographers. His maps of the eastern colonies were produced from 1737 until 1755, and are credited with being more accurate and with more detail than those of his contemporaries. The first, Map of the Walking Purchase, 1737, was found in the papers of James Logan, a mathematician who held many government positions. The second, A Map of Pennsilvania New Jersey, and the Three Delaware Counties, published in 1749, was the product of years of collecting data and maps, and communications with the men listed above and others. In addition, Evans traveled both alone and on the famous trip from Philadelphia to Oswego in the company of Bartram and Weiser with a sextant, level, and other instruments for mapping. A second edition was published in 1752. His best known map, A General Map of the Middle British Colonies in America, was published in 1755. During that time period Evans published a number of articles including his Analysis of the 1755 map with many prescient observations about topography and geology.