For many centuries the going down of the sun marked a cessation of man’s labors, and among his first efforts toward increasing his efficiency was the prolongation of his hours of vision by artificial illumination. Beginning with a shell for a lamp, a rush for a wick, and the fat of his game for oil, the first crude lamp was made, and while it shed but a feeble and flickering light, man ceased to go to sleep with the fowls and the beasts, and continued his labors and amusements into the night. For many centuries the lamp held its exclusive sway, and probably will ever find a useful place; but with the discovery of coal gas and its practical manufacture the nights of the Nineteenth Century have been made to represent illuminated illustrations of the world’s progress. Coal gas can hardly be claimed as an invention, however, for natural gas from the bowels of the earth had been observed and used in China from time immemorial. The holy fires of Baku on the shores of the Caspian and elsewhere were also thus supplied. The first steps toward its artificial production began in the latter part of the Seventeenth Century with Dr. Clayton. Bishop Watson, in 1750, and Lord Dundonald, in 1786, also experimented with combustible gas made from coal, but the man who more than any other contributed to its practical manufacture and introduction was Mr. Murdoch, of Redruth, Cornwall, England. In 1792 Murdoch erected a gas distilling apparatus, and lighted his house and offices by gas distributed through service pipes. In 1798 he so lighted the steam engine works of Boulton & Watt, at Soho, near Birmingham; and in 1802 made public illumination of the works by this means on the occasion of a public celebration. In 1801 Le Bon, of Paris, used a gas made from wood for lighting his house. In 1803-4 Frederick Albert Winsor lighted the Lyceum Theatre, took out a British patent No. 2,764, of 1804, for lighting streets by gas, and established the National Light and Heat Company, which was the first gas company. In 1804-5 Murdoch lighted the cotton factory of Phillips & Lee at Manchester, the light being estimated as equal to 3,000 candles, and this was the largest undertaking up to that date. In 1807 Winsor lighted one side of Pall Mall, London, and this was the first street lighting. A disastrous explosion occurred shortly afterwards, and such eminent men as Sir Humphrey Davy, Wollaston, and Watt expressed the opinion that it could not be safely used; but the so-called “coal smoke” had come to stay, and in 1813 Westminster Bridge and the Houses of Parliament were lighted with gas. In 1815 there was general adoption of gas in the streets of London, and shortly afterwards in Paris. In 1805-6 David Melville, of Newport, R. I., invented a gas apparatus and lighted his house with it. He took out United States patent March 18, 1813, and in 1817 contracted with the United States to supply for a year the Beaver Tail Lighthouse. In 1815 James McMurtrie proposed the lighting of the streets of Philadelphia; Baltimore commenced the use of gas in 1816, Boston in 1822, and New York in 1825.

In Fig. 222 is shown a diagrammatic illustration of the principal features of a gas works, as employed throughout the greater part of the Nineteenth Century. On the left is seen the furnace, in which is arranged above the fire a series of retorts, which are in the nature of horizontal closed cast iron boxes. Only one of the series is visible in the view. Their ends project out beyond the furnace walls, and have doors for giving access to the interior, and each retort outside the furnace is connected by an upright pipe to an elevated cylinder called a hydraulic main. When the retort is charged with coal through its end door, and is heated red hot by the subjacent fire of the furnace, a heavy gas is driven off from the coal, which passes up the pipe to the hydraulic main, where it partially condenses and leaves its heavier portions in the form of coal tar and ammoniacal liquor. The gas then passes through the series of bent pipes, which form a condenser, where other remaining portions of the tar and other impurities are condensed, and drawn off from time to time in the little well shown on the left of the coil. From the condenser coils the gas passes into the purifier, shown on the right of the coils as an enclosed case having a series of shelves on which is spread slaked lime, which takes up from the gas impurities in the form of sulphuretted hydrogen and carbonic acid. From this purifier the gas passes downwardly through a pipe into a large gas holder whose lower end is sealed in a water tank, and which gas holder is balanced by weights and chains passing over pulleys. With the gas holder, the distributing mains of the city are made to connect to receive their supply. When the gas holder is full it is buoyed up by the lighter gas, and occupies an elevated position, and as its supply is used up, the gas holder settles down into the water.

In the operation of gas making many valuable secondary products are formed. The coal in the retorts is not entirely consumed, but is reduced to the condition of coke, and in this form is sold for fuel. The ammoniacal condensations are purified to form ammonia, while the coal tar, which but a few years ago was little more than a waste material, is now a valuable commercial product, being extensively used in the manufacture of the aniline, phenol, and naphthalene dyes, also in medicines and perfumes, and being used in crude form also as an important element in street paving compositions.

Water Gas.—In 1875 an important era in gas making was inaugurated by the introduction of what is known as “water gas,” so called for the reason that water in the form of steam is decomposed and its hydrogen, mixed with carbonic oxide gas, is mingled with a heavier carbon gas from oil, and is converted at a high temperature into a permanent, stable illuminating gas, at a much lower cost than coal gas.

Fontana was the first to notice the decomposition of steam by incandescent carbon to form hydrogen and carbonic oxide. Ibbetson’s British patent, No. 4,954, of 1824, represents the first application of this principle. This was followed by Alexander Selligue, who, in 1834, obtained a French patent, No. 9,800, and in 1842 produced water gas at Batignolles, a suburb of Paris. Sanders’ United States patent, 21,027, July 27, 1858, was the basis of an experiment tried at the Girard House in Philadelphia. These, with Siemens’ British patents, Nos. 2,861, of 1856, and 972, of 1863, for methods of constructing furnaces, constitute the earlier steps in the development of water gas, although many other patents were granted prior to the latter date for various methods and forms of apparatus. The practical production and successful commercial use of water gas, however, began with T. S. C. Lowe, who obtained United States patent No. 167,847, September 21, 1875, and revolutionized the gas making industry. In less than a dozen years from the date of his patent 150 cities and towns in the United States were using water gas, and in 1886 the Franklin Institute gave to Mr. Lowe a grand medal of honor for his invention, which of those exhibited that year was believed to contribute most to the welfare of mankind by cheapening the cost of light. Fig. 223 represents an illustration of the Lowe apparatus as shown in his patent, and whose operation is as follows: Valves 9 and 10 being open, an anthracite coal fire in generator chamber 1 gives off carbonic oxide gas, which passes down pipe 2 and enters the base of superheater 3, where mixing with air coming down pipe 4, it burns to form an intense heat. The chamber, 3, is filled with loose pieces of fire brick, which are soon heated white hot. Valves 9 and 10 are then closed and steam is taken from an upright boiler, 6, and carried by a small pipe, 7, to the incandescent mass in chamber 3, and passing down through it is superheated. This superheated steam passes from the bottom of chamber 3 to the bottom of chamber 1, and then up through the mass of red hot coal. The intensely hot steam is thus decomposed into hydrogen and oxygen, and the oxygen unites with the carbon of the coal to form carbonic oxide gas. As hydrogen and carbonic oxide burn with only a feeble blue flame, these gases are now made richer in light giving carbon at this point by the addition of oil contained in an elevated tank, 8. This, dripping on the incandescent coal in chamber 1, is volatilized, and at the same time enriches and combines with the hydrogen and carbonic oxide to form a permanent illuminating gas (water gas) that passes up pipe 5 and through the flues in boiler 6, to outlet 13, and thence on in the usual way to the condenser, scrubber and gas holder, which are not shown, and merely act to purify the gas. As the excessively hot water gas passes through the boiler flues it furnishes the necessary heat to generate the steam. The air used in the process is forced at 12 into a drum in the smokestack, 11, and is heated by the escaping products of combustion. In practical operation there are two (or more) of the steam superheating chambers 3, working alternately, and one of them is being heated up while the other is superheating the steam.

Water gas has neither the illuminating nor the heating qualities of coal gas, and it is also much more poisonous. According to O. Wyss, one-tenth of 1 per cent. of uncarburetted water gas renders the air of a room injurious to health, and 1 per cent. is fatal to all warm-blooded animals. Notwithstanding these facts, however, its extreme cheapness and fairly satisfactory light have carried it into such general use that to-day it is said that two-thirds of all gas made in the United States is carburetted water gas.Acetylene Gas is a combination of two parts carbon and two parts hydrogen. It was discovered in 1836 by Edmond Davy, who produced carburet of potassium, and evolved acetylene gas therefrom by decomposing it with water. It was long known as klumene, and when burned it produced an intense white light. For a long time it was only produced in a small way in the laboratory. It is now made commercially by the mutual decomposition of water and calcium carbide, the latter giving off, when brought in contact with the water, acetylene gas, which rises in bubbles. In the reaction the carbon of the carbide unites with a portion of the hydrogen of the water, producing acetylene gas (C₂H₂), while the calcium of the carbide unites with the oxygen of the water and the remaining portion of the hydrogen and forms calcium hydrate, or slaked lime, which precipitates as a slush.

The union of carbon with an alkali metal, first accomplished by Davy in 1836, was followed in 1861 by the combination of carbon with calcium by Wohler. It was not, however, until the electrical furnace became an agency in chemical reaction that calcium carbide was made on a commercial scale. The production of acetylene gas for illuminating purposes began with the operations of Thomas L. Willson in 1893, and his patents, Nos. 541,137 and 541,138, of June 18, 1895, and 563,527 and 563,528 of July 7, 1896, cover the chemical process, the product, and the mode of operating. The reaction is a very simple one. A mixture of lime and carbon is subjected to the heat of an electric arc, and the carbon combines with the calcium of the lime to form calcium carbide, which appears on the market as dirty black stone-like lumps. The simplicity of the method of generating acetylene gas from this substance by merely bringing it in contact with water has greatly stimulated invention in this field. The art began practically in 1895, and since that time more than 500 patents have been granted for acetylene gas apparatus.

A very simple apparatus for the purpose is shown in Fig. 224, in which a vessel containing water has an inverted bell or cylinder within it, open at its lower end. A basket or cage is suspended within the inner cylinder, and contains a few lumps of calcium carbide, which are first immersed in the water by being forced down by the rod supporting the same, which passes through a stuffing box. Acetylene gas is immediately generated and its pressure forces the level of the water down in the inner cylinder, causing it to rise in the annular space between said cylinder and the case. As the water level descends in the inner chamber it passes out of contact with the calcium carbide, and the generation of gas is discontinued until some of the gas is drawn off or consumed at the burners, whose pipe is shown connecting with the gas space of the inner cylinder. When so drawn off, the pressure in the inner cylinder is relieved, and the water therein rises to contact again with the calcium carbide and renews the generation of gas. This principle of automatic action is a very old one, and will be recognized by the student as that of the Dobereiner lamp of the chemical laboratory, invented by Prof. Dobereiner, of Jena, in 1824.

In acetylene gas apparatus a great variety of methods are employed for bringing the water and carbide into contact. Instead of the automatic pressure level principle described, many devices discharge a regulated quantity of powdered calcium carbide into the water, while in another form the water is discharged upon the calcium carbide. An example of the latter is given in Fig. 225, which represents the Criterion generator. A number of receptacles containing charges of calcium carbide are made to successively receive a regulated quantity of water, the gas being collected in a rising and falling holder.

Acetylene gas finds its principal uses for isolated plants, and in country houses. One form of using it is to compress it under high tension in cylinders, but this method has been attended with some disastrous explosions, and is discriminated against by the insurance companies.

Calcium carbide is now made in a large way by the Willson Aluminum Company, at Spray, N. C., and also at Niagara Falls and at Sault St. Marie, Mich., and its cost is between 3 and 4 cents per pound.

Acetylene gas has an acrid, garlicy odor, and burns with an intensely white flame, and so superior is it to coal gas in illuminating power that it only requires a pipe of one-third the diameter of that used for coal gas to produce the same illuminating effect.Carburetted Air is another form of illuminating gas which has found some useful applications. This consists simply of air forced through some light hydrocarbon, such as naphtha, benzine or gasoline, and so saturated with the vapors of these volatile substances as to become an inflammable mixture. Many patents have been granted for apparatus operating on this principle, and it has been put to some practical use in country houses, and seaside resorts.Pintsch Gas is another special application. It is a gas made from oil and compressed in storage cylinders by means of pumps for portable use. It is stored under a pressure sometimes as high as 150 pounds to the inch, its pressure being reduced at the burners through the agency of pressure regulators. It is used for lighting railway cars, buoys, and lightships.Gas making has probably been the most extensive and important of all the commercial chemical operations of the Nineteenth Century, and with it has come a great array of minor inventions as accessories. Among these first came the gas meter and pressure regulator. With the introduction of gas into houses some means of determining the amount consumed as a basis of payment was required, and for this purpose the gas meter was devised. The first gas meters were known as wet meters, and effected a measurement by passing the gas through a liquid and rotating a wheel therein. The wet meter was invented by Clegg (British patent No. 3,968, of 1815), and the dry meter, by Malam (British patent No. 4,458, of 1820), and improved by Defries (British patent. No. 7,705, of 1838). The gas regulator is simply a little automatic apparatus whereby the variation of pressure in the gas main is reduced and the flow rendered perfectly uniform at the burner. It effects a saving of gas by preventing it from blowing when the pressure is too great, and also gives a more steady and uniform light.

Among the great number of mechanical devices which have grown out of the use of gas may be mentioned the gas range for heat, the gas engine for power, and the Welsbach burner for light. The gas range has contributed much to the domestic economy of the city house. It gives an immediate heat in the kitchen for all culinary and domestic purposes, without the incidental objections of having to transport fuel and remove ashes. It is put into or out of action in an instant, saves labor and time, and avoids the heat and discomfort of a coal stove during the hot months of summer. It is organized in principle after the Bunsen burner, whereby a perfect combustion of the carbon is obtained with maximum heating effect and without smoke or deposits of lampblack.

The Otto gas engine, seen in Fig. 226, is a pioneer and representative type of a great number of explosive gas engines, which in recent years have become active competitors of the steam engine where only small power is required. The Otto engine is covered by patent No. 194,047, August 14, 1877. Patents No. 222,467, 297,329, 336,505, 358,796, 320,285, 386,211 and 549,160 represent important developments in this art.

The Welsbach burner for improving the quality of gaslight, and economizing its consumption, is also well and favorably known. It utilizes the Bunsen burner principle to make a very perfect combustion of the gas, with the greatest possible heat and the least smoke, and then directs its great heat on to a refractory body which will not burn, but glows with a brilliant white incandescence. The Welsbach burner was brought out in 1885. The United States patent therefor was granted October 7, 1890, to Carl Auer Von Welsbach, No. 438,125. The Welsbach light is a development of the Drummond, or limelight, invented by Lieut. Drummond, of England, in 1826. This latter exposed a piece of quick lime to the intensely hot flame of the oxy-hydrogen blow pipe, which was invented by Dr. Robt. Hare in 1802. The piece of lime glows with an intense brilliancy approximating that of the electric light. The Welsbach burner, see Fig. 227, operates on the same general principle, except that the refractory body, which is heated to incandescence, is a tubular sleeve of netted fabric first steeped in a solution of the salts of refractory earths, and then incinerated by heat to burn out the textile fibre and leave the refractory earthy oxides as a skeleton of the fabric, and which is called a “mantle.” This mantle is suspended above the flame arising from a proper admixture of air and gas, and is heated thereby to a brilliant incandescence which furnishes the light. In the Welsbach burner the light seen does not proceed directly from the combustion of the gas, but from the white hot mantle. The light is a very pure white one, does not distort or falsify colors, and effects a great saving of gas. An important improvement upon the mantle is covered by Rawson’s patent, July 30, 1889, No. 407,963, for coating the mantles with paraffine or analogous material to toughen them and prevent them from breaking in packing and transportation.

Natural Gas.—No review of gas lighting would be complete without some reference to the development incident to the use of the natural gas flowing from the internal reservoirs of the earth. Such gas has been known and utilized for centuries in China, and was conveyed by the Chinese in bamboo pipes to points of utilization. The discovery of coal oil in the United States in 1859, and the great advances made in the methods and apparatus for sinking oil wells, have resulted in the discovery of numerous wells of natural gas, whose values were quickly perceived and utilized by their owners. The village of Fredonia, N. Y., was probably the first to be lighted by natural gas, and a flow from a well at West Bloomfield, N. Y., opened in 1865, was carried in a wooden main more than twenty miles to the city of Rochester. Many wells of natural gas have since been found at various points, and so extensive has been its use for cooking, heating, lighting and metallurgical processes, that thousands of patents have been taken for various forms of burners, pressure regulators and other appliances for utilizing the same. The annual production of natural gas in the United States for 1888 was valued at $22,629,875. There has, however, been a steady decrease in the past ten years. The amount produced in 1897 was $13,826,422. The insatiable demands of modern civilization must some day exhaust the supply, and what will take place when the subterranean chambers are relieved of their burden is a question for the geologists to answer.