That particular quote is not from the text itself but from some of his personal notes from his trip to America. The notes are currently held at Yale. Some are online, some are not.

http://orbexpress.library.yale.edu/vwebv/holdingsInfo?bibId=4242433

The specific page you want appears to be referred to as "Yale Mss B.II.b, p. 10." If you can't find it online ask someone at your university library's research desk or the inter library loan office for assistance getting a photocopy of the document.

Yale might blow you off if it would take any effort to get it and send it to you. I ran into that problem when I was in grad school, and my solution was if I didn't get what I asked for within three weeks, I had my committee chair submit an identical request. She's a world renowned historian so they usually sent her exactly what I needed before the close of business that very day.