Lighting and Artificial Illumination

LIGHTING AND ARTIFICIAL ILLUMINATION.

From earliest times man has endeavoured to produce artificial light so as to utilize more thoroughly the hours of darkness for the purposes of work or pleasure.

Until the first application of electricity to lighting late in the 19th century all artificial light was produced by fire. The first means of securing light at night was the wood fire. To light the way a burning stick called a fire-brand or torch was picked from the fire. Resinous gum wrapped in palm leaves has served for lighting in the Malay islands and resinous materials, such as pine wood and gum, and oily vegetables and animal carcasses have been used as solid illuminants.

Candles.

Wax candles are probably of Phoenician origin. The tallow candle is of later origin, probably the second century A.D. About the 11th century splinters of wood dipped in tallow were first used in England. The whale oil industry in the middle of the 18th century introduced spermaceti for candles. Stearin was first used about 1840. "Composites," candles made of stearic acid and stearin, were the first to require no snuffing. The corn posite candle of the present day is made of stearin and paraffin. (See CANDLE.) Oil Lamps.--Oil lamps had their origin several thousand years B.C. The prehistoric lamp was probably made of stone; later clay and terra-cotta lamps were used. These lamps had one wick and a reservoir for oil or grease. The Eskimo lamp consisted of a soap stone dish in which was placed a wick made of moss rubbed into a fine powder; oil was obtained from blubber. Cave-dwellers probably used a skull burning fats taken from animals killed in the hunt. In 1787, the Genevan physicist Argand introduced a draft up through the centre of the burner. Later a "camphene" lamp with long tubes employing a chimneyless, double, flat wick, had some use. (See LAMP.) Gas Lamps.—The Chinese probably first used "gas" for light ing, by piping natural gas in bamboo tubes from salt mines. A natural gas well underlying a ditch of water near Wigan, in Lancashire, England, was closely related with the evolution of artificial illuminating gas. About 1664, the Rev. Dr. John Clayton drained the water from the Wigan "ditch" and found that the gas came from the ground. A coal-mine was nearby and Dr. Clayton

suspected a relationship. He distilled coal in a retort, and suc ceeded in collecting some of the coal gas in bladders. In more than a century later, Jean Pierre Minckelers, a professor at Louvain university, distilled many substances, including coal, and in 1785-86 lighted his lecture room with gas. In 1792 William Murdock similarly lighted his home. Phillippe Lebon patented in 1799 the "thermo-lampe," a self-contained apparatus for the production of gas by distillation from wood, coal and other similar solids. In 1802 Murdock introduced "Bengal lights" (flaming open burners). The firm of Boulton and Watts spent large sums on experiments on burners made by Murdock, who used a tallow candle burning 175 grains per hour as the standard of comparison in his gas photometry. Early burners were the "cockspur" and "cockscomb," an adaptation of the Argand burner to gas lamps and the "bat-wing" burner. J. B. Nielson of Glasgow, in 1820, introduced the fish-tail burner in which two impinging flames spread into a flat, fan-shaped sheet. In i8o6 F. A. Wintzler, a German, lighted the Lyceum theatre in London, and under his supervision, the first gas mains were laid in a public street in Pall Mall. Sheet lead was used, being bent cylindrically and soldered at the edges. Wintzler may be called "the father of the central station idea," for he headed in 1810 the first company attempt ing to supply lighting service to the public, The London and West minster Chartered Gas Light and Coke Company. He was greatly assisted in this work by the engineering skill of Samuel Clegg. Goldsworthy Gurney in 1826 showed that a cylinder of lime could be made dazzlingly brilliant by the oxy-hydrogen blowpipe. About 1838, W. H. Fox Talbot discovered that even the feeble flame of a spirit lamp will heat finely divided lime to incandes cence. Gillard, who introduced the intermittent process of manu facturing water-gas, made a mantle of fine platinum gauze to fit over the flame, but the rapid erosion of the platinum made it useless in a few days.