Sift the flour. Place in a bowl and add baking powder, salt and sugar. Sift again to mix and then rub in the butter. Place the buttermilk in a pitcher and add the baking soda. Stir to thoroughly dissolve the soda and then use this to mix the flour to a dough. Knead well in the bowl with a spoon and then turn on a slightly floured board and roll or pat out one inch thick. Cut with a large biscuit cutter and brush the top with butter and bake in a hot oven for eighteen minutes.
