Here is another envelope. Wonder what Carnac the Magnificent would say about it? I need his help on this one because I do not know much about this reading series. 640 East 6th, Apt. 15 was Carl Weissner's apartment in NYC. Panic Press was his publishing outlet. In 1967 or so, Carl came over from Germany and headed up to Gloucester to see Charles Olson in preparation for a planned gradute thesis. Olson told Carl to drop the thesis and take his tape recorder across the central fact of America (SPACE) and do some exploratory field work. Carl took his advice.
Carl taped everything so I would suspect these readings from March 1968, were as well. Yet as Dirk Diggler says about demos for Feel My Heat, "Where are the tapes?" See http://www.youtube.com/watch?v=SYzB_QqxXu4. I do not think they made it to Northwestern or University of Texas.
Jackson MacLow was no stranger to the NYC reading circuit. A few years earlier, he was part of the Light Years reading series along with Carol Berge in the coffehouse scene. Carl's events seem more like a loft party type situation. I think he stayed at the Hotel Chelsea at various times as well, but in March 1968, it does not appear that he had a room there.
I should email Diane di Prima about it. Carl being Carl would have gotten a chuckle out of the typo of di Prima's name. Like with his mentor Burroughs, such "mistakes" spoke volumes.