Put into a cask a mixture composed of five gallons of water, two gallons of whiskey, and a quart of strong yeast, stirring in two pounds of powdered charcoal. Place it where it will ferment properly, leaving the bung loose till the fermentation is over, but covering the hole slightly to keep out the dust and insects. At the end of four months draw it off, and you will have a fine vinegar, as clear and colourless as water.