Author Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1845 Excerpt:...instead of 81.75, yet it consumes so much faster, as thereby to compensate fully for this difference. When a tallow candle of 6 to the lb. is not snuffed, it loses in intensity, in 30 minutes, 80 hundredths; and in 39 minutes 86 hundredths, in which dim state it remains stationary, yet still consuming nearly the same proportion of tallow. A wax candle attains to its greatest intensity of light when its wick has reached the greatest length, and begins to bend out of the flame. The reason of this difference is, that only the lower part of the wick in the tallow candle is charged with the fat, so as to emit luminiferous vapor, while the upper part remains dry; whereas, in the wax candle, the combustible substance being less fusible and volatile, allows a greater length of the wick to be charged by capillary attraction, and of course to emit a longer train of light. The following table contains, according to Peclet, the illuminating powers of different candles, and their consumption of material in an hour; the light emitted by a fareel argand lamp, consuming 42 grammes (= 42 X 15i grains) in an hour, being called 100:--The subjoined table shows the economical ratios of the candles, where the second column gives the quantity of material in grammes which is requisite to produce as much light as the Carcel lamp:--These results may be compared with mine given above. A kilogramme, or 1,000 grammes= 15,440 grains=2j lbs., avoirdupois. INDIGO. Imported for home consumption, in 1839, 2,704,396 pounds; in 1840, 2,996,215; duty 3d. on West Indian, id. on East Indian. INK. Mr. Stephen's patent blue ink is made by dissolving Prussian blue in a solution of oxalic acid. IRON. For certain new processes for making malleable iron, Mr. W. N. Clay has obtained two successive pate...