As always, we learned more history in Phila than the Founders intended, not least from the great street signs everywhere documenting where it all began. One of two illuminating exhibitions at the African American Museum of Philadelphia was on Pearl Bailey, who, it turns out, was also a cookbook author and once attempted a cooking show on the teevee (which was not picked up). What we also learned was that even Richard Nixon had more class than the white supremacist now squatting in the house built by enslaved people. He had Bailey and her husband, Louis Bellson, perform there — and he appointed her “ambassador of love.” Clearly he was hammered, tho: Signage on the wall sez he started playing “Home on the Range” and she stopped him with “I want to sing a song, not ride a horse.”