Preheat oven to 350. Sift together the flour, salt, ginger, and cinnamon. Stir the soda into the molasses. Melt the butter in the boiling water. Turn both wet mixtures into a bowl and stir in the flour mixture. Add more flour if needed, but keep the dough as soft as can be handled. Drop by teaspoonfuls unto an greased cookie sheet.
Bake until just turning brown at the edges. This recipe will make about twenty cakes.