Salt Rising Bread

3 medium potatoes, peeled and sliced
3 tbs corn meal
1 tsp sugar flour
4 cups boiling water
2 cups lukewarm milk
1 cup water
1/8 tsp baking soda
1/8 tsp salt
2 tbs melted shortening

Boil 4 cups water in medium pot. Remove from heat and add potatoes, corn meal, salt, and sugar. Cover pot with cloth and keep in a warm place overnight. Take out potatoes, add milk, soda, second salt, and shortening. Add enough flour to make dough stiff when kneading on a floured surface. Form into four loaves and let dough rise to double. Place on cookie sheet and bake in cardboard oven at 400 until top is slightly browned.