To three gallons of brine strong enough to bear an egg, add one quarter pound good loaf sugar, and one tablespoonful of salt petre; boil the brine, and when it is cold strain carefully. Pack butter closely in small jars, and allow the brine to cover the butter to the depth of at least four inches. This completely excludes the air. If practicable make your butter into small rolls, wrap each carefully in a clean muslin cloth, tying up with a string; place a weight over the butter to keep it all submerged in the brine. This mode is most recommended by those who have tried both.