A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . aradays burneris in use at Buckingham Palace, Windsor Castle, the ?House of Lords, and in many publicbuildings. Ox THE Estimation of the Value of Illuminating are two methods in use for estimating the illuminating value of gas, viz.:—Lst. The photometric Chemical analysis. The photometric method consists in comparing the intensity of the light emitted by agas flame, consuming a known volume of gas, with that yielded by some other source ofli
A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . aradays burneris in use at Buckingham Palace, Windsor Castle, the ?House of Lords, and in many publicbuildings. Ox THE Estimation of the Value of Illuminating are two methods in use for estimating the illuminating value of gas, viz.:—Lst. The photometric Chemical analysis. The photometric method consists in comparing the intensity of the light emitted by agas flame, consuming a known volume of gas, with that yielded by some other source oflight taken as a standard. The standard eiii])loyed is usually a spermaceti candle, burningat the rate of 120 grains of fii)erm per hour. A spermaceti candle of six to tlie poundusually liuriis at a somewhat quicker rate than this ; but in all cases the consumption ofsperm Ijy the candle during the course of each experiment ought to be carefully ascertainedby weighing, and the results obtained corrected to the 120-grain standard. Thus, supposethat during an experiment the consumption of sperm was at the rate of 130 grains per. COAL-GAS. MS hour, and that the gas flame being tested gave a light equal to 20 such candles, and it is re-quired to know the light of this tlame in standard 120-grain candles, then— 120 : 130 : : 20 : 21-7;or, 20 candles burning at the rate of 130 grains per hour, are equal to 2r7 candles burningat the rate of 120 grains per hour. There are two methods of estimating the comparative intensity of the light of the gasand candle flames, both founded upon the optical law that the intensity of light diminishesin the inverse ratio of the square of the distance from its source. Thus, if a sheet of writ-ing paper be held at the distance of one foot from a candle, so that its surface is perpen-dicular to a line joining the centre of the sheet and the flame, it will be illuminated with alight four times as intense as that which would iiill upon a sheet of paper h
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Keywords: ., bookcentury1800, bookdecade1860, bookpublishernewyo, bookyear1864
