In the thirty years preceding 1900, the United States was, in a number of important respects, an underdeveloped country. Despite the existence of some components of modern manufacturing technology, e.g., interchangeable parts, the country was still predominantly agricultural. In 1870, 37% of all personal property was in and on farms, and as shown in Tables 2-5, pages 5-9, the economy was also predominantly agricultural and extractive, as is the typical underdeveloped country. Further, although American society was, for the 19th century, unusually open, and free of impediments to factor mobility, certainly class and probably caste distinctions were not uncommon. In general, however, 19th century factor flows and commerce were impeded little in comparison to other countries at that time, and in LDC’s today.