Cream the butter; add the sugar and beat until light and fluffy.
Dissolve the baking soda in the water and add, stirring well.
Add the oatmeal and ginger, mixing well. The mixture should be fairly firm. If necessary, add a little more oatmeal.
Knead lightly on a floured surface.
Preheat oven to 300 degrees.
Press the mixture in a buttered baking dish, about 8 x 12 inches. The dough should be about 1/2 inch thick.
Bake in the 300 degree oven for 35 minutes, or until brown on top.
Cut into squares while hot.
