21. December natural gas slipped 9.1 cents to $ 8.684 per million British thermal units . 22. December natural gas rose 24.2 cents to $ 7.115 per million British thermal units . 23. September natural gas rose 6.8 cents to $ 1.539 per million British thermal units . 24. December natural gas fell 6 cents to $ 7.176 per million British thermal units . 25. January natural gas declined 3.6 cents to $ 6.82 per million British thermal units . 26. September Natural Gas up 0.9 cent to $ 1.559 per million British Thermal Units 27. January natural gas slid 80.2 cents to $ 7.837 per million British thermal units . 28. April natural gas jumped 8.3 cents to $ 2.178 per million British Thermal Units . 29. A therm is a unit of gas measurement equivalent to 100, 000 British thermal units . 30. September Natural Gas up 3.3 cents to $ 1.523 per 1 million British Thermal Units
