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INTRODUCTORY OBSERVATION. Page I;

Progress of the arts. — Influence of it upon the morals and con-dition of man.—Beneficial tendency of chemical and mechanicalimprovements.—State of pre-eminence of people with regard tocivilization.—How to be estimated.—Flourishing state of thosenations which have shown the greatest activity in cultivating theuseful arts, and establishing useful enterprises.—General obser-vations on this subject.—Extraordinary discoveries of moderntimes.—New art of procuring light.—Object of the treatise.

PART I.

PRODUCTION OF ARTIFICIAL LIGHT . &c. 8;

Production of the flame generated during the combustion of certainbodies.—Characters of flame when perfect.—Most luminousflame, how produced with the least consumption of combustiblematter.—Conditions necessary for that purpose.—Importance ofthis subject, with regard to the production and supply of arti-ficial light.—The flame of bodies may be tinged-—Blue flame,red flame, green flame, &c.—Opinion concerning the origin oflight emitted by bodies burning with flame;—Philosophy ofthe subject;—Theory of the action of the instruments of illumi-nation.—Rude method of procuring light employed in somecountries.—Chemical action of candles and lamps.—Agency ofthe tallow, oil, &c.—Office of the wick.—Reason why tallowcandles require snuffing, and wax candles snuff themeslves—Further observations on the subject.

METHOD OF ASCERTAINING THE ILLUMINATING POWER OF CANDLES, LAMPS, ANDOTHER LUMINOUS BODIES. 22.

,.Optical principle assumed as law for determining the relativestrength of lights of different kinds.—Admeasurement of theintensities of light.—Quantity of wax, tallow, oil, &c. requisitefor producing a light of a certain Strength.—Method of increasing the light of tallow candles, and to obviate the necessity ofsnuffing them.—-A tallow candle placed in an inclined positiongives more light than when placed perpendicularly and snuffedwith an instrument.—Explanation of the fact.—Further observa-tions on this subject.—-Comparative cost of the light obtained byburning tallow candles of different sorts and sizes;