High pressure lighting units are supplied with gas by pipe lines connected with a com pressor, which by automatic control delivers the gas at the pressure required, or they may be connected direct with mains carrying gas at considerably higher pressure, the pressure in. the lines leading to the lamps being controlled by individual reducing governors. High pres sure gas lighting has been extensively uced abroad for street and ornamental fighting wherever high power units are required. The principal streets of London, Paris, Vienna and Berlin are so lighted with units ranging from 250 to 4,500 candle power each. These lamps are supplied by special steel mains from central compressor stations and as they are independ ent of the regular distribution gas mains, are lighted automatically from these central stations. A large section of the grounds of the Panama Pacific Exposition in 1915 at San Francisco was lighted by over 300 1000-candle-power units of ornamental design. These units were equipped with automatic regulators, which de livered the gas at three pounds pressure per square inch, taken from the main distribution system, which carried gas into the grounds for all purposes at 35 pounds per square inch. The general use of high pressure gas for light ing and heating will necessarily be a gradual process on account of the conditions and legal regulations imposed upon the gas industry since its inception when gas was used only for lighting with the appliances then known. The
Weisbach mantle was invented in 1886 and soon afterward came into general use, rapidly dis placing the flat flame burners, as its superiority was appreciated and recognized. Notwith standing this radical change in the use of gas for illumination, the old legal regulations re stricting gas pressure and specifying the illu minating power of the gas to meet the require ments of an obsolete appliance still are en forced, thereby seriously deterring the ad vancement of the use of gas for lighting, as well as heating. The same principles which make gas valuable as an illuminating agent apply to its use for heating purposes. Many industrial establishments utilize the advantages of high pressure gas for fuel by installing in dividual compressor outfits. High pressure lighting may be termed an advance of the art years ahead of the physical condition of the in dustry. When the legal restrictions referred to are removed, gas will be supplied on the basis of its heating value and at pressures which will ensure the general enjoyment of its latent quali ties as demonstrated by high pressure lighting.