Pour four tablespoonsful of good vinegar into a small stew-pan, and add some peppercorns and salt. Let this boil till reduced one-half; let it cool, then add to it the well-beaten yolks of four or five eggs, also four ounces of butter, more salt if necessary, and a very little nutmeg. Set the stew-pan on a very slow fire, and stir the liquid till about as thick as cream, then remove it immediately. Now put this stew-pan into another pan containing a little warm water kept at the side of the fire. Work the sauce briskly with a spoon, or with a little whisk, so as to get it frothy, adding little bits of butter (about as much as half the size of an egg). When the sauce has become light and smooth it is ready for use. It is used for boiled fish, cauliflower or asparagus.