Cream the shortening and sugar. Sift the spices and flour and baking powder together. Beat the ½ teaspoon soda into the molasses until it is light and fluffy, and add to the shortening and sugar. Add the ¼ teaspoon soda to the boiling water, and then add it alternately with the sifted dry ingredients. Fold in the beaten egg when all is well mixed, pour into a greased and floured pan, and bake about 20 minutes, at 325°F. This mixture will seem much too thin to make a cake, but do not increase the quantity of flour, as many doubting cooks have tried to do.