Sift the flour and salt and baking powder together. Beat the yolks of the eggs till very light. Beat the whites to a stiff froth. Add the melted butter to the milk, which should be scalded and grown luke warm, and then mix in the whites of the eggs. Now add the flour gradually, making a nice, light batter. If it appears at all stiff, add a little more milk. Have your waffle irons ready, thoroughly heated. Have at hand a small brush or a stick with a piece of clean, fringed cloth wrapped around the end. Dip this in a little melted lard, and brush over the interior of the irons, till every part is greased. Pour the batter into a pitcher, so that you may the more easily fill the irons. Fill until the elevations are lightly covered, and then close the irons quickly and turn it over. Bake the Waffle about two minutes, or till a nice, delicate brown. Carefully remove from the irons, place in a hot plate or waffle dish in the mouth of the oven, and proceed with the baking. Send to the table very hot.