Pick over the beans, rinse them, and put them in a large heavy pot with the water. Cover the pot and bring the water quickly to a boil. Stir the beans, remove them from the heat, and allow them to sit for 1 hour. When the beans have softened, return the pot to the heat, adding more boiling water if necessary. Then add the remaining ingredients, with the exception of the rum. Continue to cook, covered, over low heat for several hours, until the beans are very tender and the ham falls off its bone. Remove from the heat and remove the ham hock bone and meat. Dice the meat finely and discard the bone. Press the remaining ingredients through a food mill, taste for seasoning, and add the diced ham. At this point, the soup can rest overnight in the refrigerator so that the flavors mingle, or it can be served at once. To serve, reheat the soup for 5 minutes while stirring in the rum. Side dishes of lemon wedges, cooked white rice, minced onion, or chopped hard-boiled eggs can be served as garnishes. Serves 6.Subj: Frijoles SOPA DE FRIJOL NEGRO