No ... apart from being fast and having repeating phrases, the first and last pieces are not at all alike. Consider the rhythms: Found Harmonium is in common time; that and the regular modular phrasing are what make it suitable for adaptation into an Irish reel. Whereas Perpetuum Mobile is in a totally irregular rhythm which causes any attempt to beat a regular rhythm on it to make the phrases fold over and overlap and never come to a conclusion, which is why it's a perpetuum mobile.