There is some speculation as to who (or what) Langdon Alger means, but nothing concrete has been found.\n\nThe link I have provided below lists some speculations as to who the name might be based on.  Should be about halfway down the page.  Do a search on the page for Langon Alger and you'll find it right away.
in simpson episode 3f17 bart on the road, Lisa says her boyfriend is Langdon Alger.  What is the Joke?