1 Chaldron of Coke, weighing 1494 lbs. 12 Gallons of Tar ” 135 ” 12 Gallons Ammoniacal liquor 100 ” 9500 Cubic feet of Gas, weighing 291 ” Loss (chiefly water) ” 220 ” -------- 2240 lbs. A cubic foot of gas weighs 514 and a-half grains.