metallurgical operations.—Mode of obtaining it in the gas-light process.—Sort of coke best adapted for kitchen and parlour fires.—Manufacture of it.—Coal tar.—How obtained.—Its properties.—Earl of Dundonald’s method of manufacturing tar from coal.—Quantity of coal-tar produced in the gas-light process from a given quantity of coal.—Characters of coal tar obtained from Newcastle coal, differ from that produced from canel coal.—Coal pitch.—Process for obtaining it.—Properties of coal-pitch.—Use of it in the arts.—quantity of coal-pitch obtainable from a given quantity of tar.—Ammoniacal liquor produced during the distillation of coal.—Its chemical constitution.—Quantity obtained from a given quantity of coal.—General observation respecting the scheme of applying coal-gas as a substitute for candles and lamps.—Effects which it must produce upon the arts and upon domestic economy.—Its views.—Primary advantages.—Resources which it presents to industry and public economy.—In what respect it is entitled to public approbation and national encouragement.—Effects of prejudice against the introduction of new and useful discoveries.—Have operated strongly in retarding the gas-light illumination.—Remarkable slowness with which improvements of extended utility make their way into common use, contrasted with the rapid adoption of fashionable changes.—Other causes unfavourable to the adoption of new and useful plans.—Further observations on this subject.—The new system of lighting with coal-gas can never supersede the use of candles and moveable lights.—Gas-light illumination cannot prove injurious to the Greenland fishery—nor can it diminish the coal trade—must prove beneficial to it.—The price of coal even when it is the highest cannot materially affect the beneficial application of gas-lights.—Striking advantages to be derived from the introduction of gas-lights into manufactories.—Principal expense which must always attend the gas-light illumination.—Is the dead capital employed for erecting the machinery.—Floating capital is small.—Advice to private individuals with regard to the erection of a gas-light apparatus calculated for their own use.—Expence which must attend the application of the new system of lighting under different circumstances.—Entire new scheme of illuminating streets, or small towns, with gas-lights; which would save all the main pipes for conveying the gas through the streets as well as the branch pipes which conduct the gas to the lamps.—Management of the gas-light machinery is extremely simple and easy.—The apparatus not liable to be out of order.—Observations on the safety of the gas-light illumination.—Misapprehension of the public concerning it.—Causes that have alarmed the public concerning the application of the new lights.—Gas-lights cannot give rise to those accidents which have so often arisen from the careless snuffing of candles, &c.—Produce no embers or sparks.—Cannot fall, or be disturbed without becoming extinguished.—Are the safest of all lights.—Impossibility of streets or towns lighted with gas to be thrown suddenly into darkness by the fracture of the gas-pipes conveying the gas to the lamps—or by the destruction of one or more of the gas-light machineries employed for preparing the gas.—Illustration showing the absurdity of such mistaken notions.—Curious self-extinguishing lamp, invented by Mr. Clegg.—His machine which measures and registers in the absence of the observer, the quantity of gas delivered by a pipe communicating with a gas-light main.—Leading characters of the new lights.—Objects and views which this art embraces.—It must lessen the consumption of oil.—Occasion a defalcation in the revenue.

TABULAR VIEW, Exhibiting the quantity of Gas, Coke, Tar, Pitch, Essential Oil, and Ammoniacal Liquor, obtainable from a given quantity of Coal: together with an estimate of the quantity of Coal necessary to produce a quantity of Gas, capable of yielding a Light equal in duration of time and intensity to that produced by Tallow Candles of different kinds. 164. DESCRIPTION OF THE GAS-LIGHT APPARATUS. 166. METHOD of correcting the relative pressure of the Gasometer, so as to cause the gas which it contains to be uniformly of an equal density. 181. DIRECTIONS TO WORKMEN ATTENDING THE GAS-LIGHT APPARATUS. 182. ESTIMATE of the price of a Gas-Light Apparatus. 185. LONDON Price List of the most essential articles employed in the erection of a Gas-light Apparatus. 186.

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ERRATA.

Page	24,	line	11,	for too, read two.
	48,		22,	for corporated, read incorporated.
	53,		7,	for this combustion, read the combustion.
	64,		24,	for Cleg, read Clegg.
	ibid		25,	for communicates, read communicated.
	65,			erase the * and put it after the word Clegg, line 24, p. 64.
	ibid		17,	for attemps, read attempts.
	125,		23,