Sift together the flour, soda, salt, ginger, nutmeg, mace, allspice, and cloves. Stir in caraway seeds and set aside. Cream the butter until light, add brown sugar, and continue creaming until fluffy. Mix in the molasses and a half cup of the flour mixture. Beat the eggs in one at a time. Add the remaining flour mixture with the buttermilk, beginning and ending with flour and beating well after each addition. Pour into a well greased and floured baking pan and bake in a moderate oven until gingerbread begins to pull away from sides of the pan and top seems springy to the touch.