Cool. I love these. The Gonzaga one was quite popular with readers as was the St. Albans ad. This is Sidwell Friends School — the name has gone through a few iterations — back in 1910. They had recently acquired property up Wisconsin Avenue (where the current campus is), formerly run by the Washington School for Boys.
Sidwell has recently been known as the school attended by White House children (Chelsea, Sasha, Malia) but did you know that Charles Lindbergh also went there? Gore Vidal, Nancy Reagan and Bill Nye the Science Guy!