“The time during which the gas-light is used may, upon an average of the whole year, be stated at least at two hours per day of 24 hours. In some mills, where there is over work, it will be three hours; and in the few where night work is still continued nearly 12 hours. But taking two hours per day as the common average throughout the year, the consumption in Messrs. Philips and Lee’s mill will be 1250 × 2 = 2500 cubic feet of gas per day; to produce which 700 weight of cannel-coal is required in the retort. The price of the best Wiggan cannel-coal (the sort used) is 13½_d._ per cwt. (22_s._ 6_d._ per ton) delivered at the mill, or say about eight shillings for the seven hundred weight. Multiplying by the number of working days in the year (313,) the annual consumption of coal will be 110 tons, and its cost 125_l._ “About one-third of the above quantity, or say forty tons of good common coal, value ten shillings per ton, is required for fuel to heat the retorts, the annual amount of which is 20_l._ “The 110 tons of cannel-coal, when distilled, produce about 70 tons of good coke, which is sold upon the spot at 1_s._ 4_d._ per cwt. and will therefore amount annually to the sum of 93_l._ “The quantity of tar produced from each ton of cannel-coal is from 11 to 12 ale gallons, making a total annual produce of about 1250 ale gallons, which not having been yet sold, it cannot yet be determined its value. “The interest of the capital expended in the necessary apparatus and buildings, together with what is considered as an ample allowance for wear and tear, is stated by Mr. LEE at about 550_l._ per annum, in which some allowance is made for this apparatus being made upon a scale adequate to the supply of a still greater quantity of light, than he has occasion to make use of. “Mr. LEE is of opinion that the cost of attendance upon candles would be as much, if not more, than upon the gas apparatus; so that, in forming the comparison, nothing need be stated upon that score, on either side. “The economical statement for one year, then, stands thus: Cost of 110 tons of cannel coal £ 125 Ditto of 40 tons of common ditto, to carbonise 20 ---- In all 145 ---- Deduct the value of 70 tons of coke 93 The annual expenditure in coal, after deducting the value of the coke, and without allowing any thing for the tar, is therefore 52 And the interest of capital sunk, and wear and tear of apparatus 550 Making the total expence of the gas apparatus per annum, about 600