“That of candles, to give the same light, would be about 2000_l._ For each candle, consuming at the rate of 4-10ths of an ounce of tallow per hour, the 2500 candles burning, upon an average of the year, two hours per day, would, at one shilling per pound, the present price, amount to nearly the sum of money above-mentioned. “If the comparison were made upon an average of three hours per day, as in most cases, would perhaps be nearer to the truth, and the tear and wear remaining nearly the same as on the former case, the whole cost would not exceed 650_l._ while that of the tallow would be 3000_l._” Mr. ACKERMAN in this metropolis, has shown that the art of gas-light illumination is not confined to great manufactories, but that its advantages are equally applicable to those on a moderate scale. The whole of Mr. ACKERMAN’s establishment, his public library, warehouse, printing-offices and work-shops, together with his dwelling house, from the kitchen to the drawing-room, has, for these four years past, been lighted with gas, to the total exclusion of all other lights. The result of the whole of this proceeding will be obvious from the following letter: To MR. ACCUM. SIR, “In answer to your request with regard to my gas-lights, which I now have in my house, I take this mode of informing you, that I charge two retorts with 240lbs. of coal, half cannel and half Newcastle, from which I extract 1000 cubic feet of gas. To obtain this quantity of gas, when the retorts are cold, I use from 100 to 110lb. of common coals; but when they are in a working state, that is to say, when they are once red hot, the carbonising fuel amounts to about 25lb. per retort. The bulk of gas thus obtained supplies 40 Argand’s lamps, of the large size, for four hours per night, during the long winter evenings, together with eight Argand’s lamps and about 22 single cockspur burners, for three hours per night: in addition to which my printers employ 16 cockspur burners for ten hours per day to heat their plates instead of charcoal fire. In the depth of winter we charge two retorts per day: but, upon an average, we work 365 retorts in 365 days. Now 365 retorts containing 120lb. of coal each, make 43800lb. which is equal to ten chaldrons of Newcastle and eight tons of cannel coal.