Bio gas from Cow dung has 55-65% methane, 30-35% carbon dioxide and the rest is hydrogen, nitrogen and other gases. Its heating value is around 600 B.T.U. per cubic foot. About one cubic foot of gas may be generated from one pound of cow manure at around 28°C. This amount of gas is enough to cook a day's meal for 4-6 people in India. About 1.7 cubic meters of biogas equals one liter of gasoline. The manure produced by one cow in one year can be converted to methane which is the equivalent of over 200 liters of gasoline. Biogas may be improved by filtering it through limewater to remove carbon dioxide, iron filings to absorb corrosive hydrogen sulphide and calcium chloride to extract water vapor after the other two processes.