Cream together butter and brown sugar until light. Add 1 cup of molasses and ½ cup warmed milk. Mix well. Mix separately the spices (ginger, cinnamon, mace, and nutmeg) and stir into the batter. Add ¼ cup brandy. In a small bowl beat eggs until light and thick. Sift together flour and cream of tartar. Stir eggs and flour alternately into the batter. Stir in the juice and rind of the orange. Dissolve 1 teaspoon of soda in 1 teaspoon of warm water and add this to the batter. Beat batter until light. Add raisins, if desired. Pour into 2 greased and floured pyrex baking dishes (8½X8½-inch size). Bake at 350 degrees for 40 to 45 minutes. Let cool in pans. Turn out on a rack to cool completely before cutting into squares. This is a very dark and spicy gingerbread, not sweet.