Crisp-Skinned Roast Chicken, via Baking Powder

Sometimes I can’t even follow my own train of thought.  I was buying some butcher's twine at a kitchen supply store because I figured it was time to learn how to truss a chicken.  I had skated around the issue for a year or so because Barbara Kafka had told me not to worry about it.  She said it was unnecessary and even detrimental to the cooking process.  But maybe that was just for her...