Melt fat with the hot water. Add baking soda and salt to the oatmeal. Make a well in the centre of the oatmeal, pour in the melted fat and water and mix to a fairly moist dough. On a board, well dusted with oatmeal, roll out as thinly as possible to an even round, dusting with oatmeal during the rolling to prevent sticking, and rubbing in more oatmeal with the palm of your hand. Cut in farls (Scotch for quarters) or rounds with a pastry cutter. Place on a baking-sheet, ungreased, and bake in a moderate oven, turning several times to prevent steaming. Bake for approximately 20 minutes, until the oatcakes are crisp and faintly golden.