"64.8585 grammes are almost exactly 1,000 grains, and 1 cubic foot of this gas will weigh 267.9 grains; then the 100 liters, or 64.8585 grammes, or 1,000 grains, are 3,761 cubic feet; 3,761 cubic feet of this gas contains 789,694 heat units, and 1,000 cubic feet will contain 210,069,604 heat units. Now, 1,000 cubic feet of this gas will weigh 265,887 grains, or in round numbers 38 lb. avoirdupois. We find that 64.8585 grammes, or 1,000 grains, of carbon contain 523,046 heat units, and 265,887 grains, or 38 lb., of carbon contain 139,398,896 heat units. Then 57.25 lb. of carbon contain the same number of heat units as 1,000 cubic feet of the natural gas, viz., 210,069,604. Now, if we say that coke contains in round numbers 90 per cent. carbon, then we will have 62.97 lb. of coke, equal in heat units to 1,000 cubic feet of natural gas. Then, if a ton of coke, or 2,000 lb., cost 10s., 62.97 lb. will cost 4d., or 1,000 cubic feet of gas is worth 4d. for its heating power. We will now compare the heating power of this gas with bituminous coal, taking as a basis a coal slightly above the general average of the Pittsburg coal, viz.: Per cent. Carbon................................... 82.75 Hydrogen................................. 5.31 Nitrogen................................. 1.04 Oxygen................................... 4.64 Ash...................................... 5.31 Sulphur.................................. 0.95 "We find that 38 lb. of this coal contains 146,903,820 heat units. The 64.4 lb. of this coal contains 210,069,640 heat units, or 54.4 lb. of coal is equal in its heating power to 1,000 cubic feet of natural gas. If our coal cost us 5s. per ton of 2,000 lb., then 54.4 lb. costs 1.632d., and 1,000 cubic feet of gas is worth for its heat units 1.632d. As the price of coal increases or decreases, the value of the gas will naturally vary in like proportions. Thus, with the price of coal at 10s. per ton the gas will be worth 3.264d. per 1,000 cubic feet. If 54.4 lb. of coal is equal to 1,000 cubic feet of gas, then one ton, or 2,000 lb., is equal to 36,764 cubic feet, or 2,240 lb. of coal is equal to 40,768 cubic feet of natural gas. If we compare this gas with anthracite coal, we find that 1,000 cubic feet of gas is equal to 58.4 lb. of this coal, and 2,000 lb. of coal is equal to 34,246 cubic feet of natural gas. Then, if this coal cost 26s. per ton, 1,000 cubic feet of natural gas is worth 9½d. for its heating power. In collecting samples of this gas I have noticed some very interesting deposits from the wells. Thus, in one well the pipe was nearly filled up with a soft grayish-white material, which proved on testing to be chloride of calcium. In another well, soon after the gas vein had been struck, crystals of carbonate of ammonia were thrown out, and upon testing the gas I found a considerable amount of that alkali,