(7)"London Proof" or "L.P." or simply "Proof" means the strength of liquor as ascertained by means of the Sykes's hydrometer or any other instrument prescribed for the purpose by the Commissioner and denotes that spirit which at the temperature of 10-55 degrees Centigrade weighs exactly 12/13th part of an equal measure of distilled water. It has a density of 0- 91984 at the temperature of 15.55 degrees Centigrade and contains 49.24 per cent by weight of alcohol and 50.76 per cent by weight of water or 57.06 per cent by volume of alcohol
