Place roast or roasts, fat side up, on a rack in an open roasting pan. Insert roast meat thermometer so the bulb is centered in thickest part. Make certain bulb does not rest in fat or on bone. Do not add water. Do not cover. Roast in a slow 325 degrees oven until done at 170 degrees. Allow approximately 2 to 3 hours (30 to 35 minutes per pound) for roasting.