Bethlehem, Pennsylvania

Interesting examples of engineering calculations and observations before the age of computers. Some books have calculations recording the Lehigh River flow and flood stages as well as New York City engineering works at the turn of the twentieth century.

The majority of the collection is comprised of letters from Ralph VanArnam Lewis (1902-1977), the bulk of which were sent between 1920 and 1955. Ralph had been a professor in the d Mathematics and Astronomy Department from 1928 to 1967. Most of the letters are between Ralph and his parents and his future wife on topics like the Bethlehem area and Lehigh. The collection also includes letters written by his brother, Lewis.