GAS (LIGHTING BY) is the best and most economical mode of obtaining artificial light as yet brought into use; though hardly known at the beginning of the present century, it has since been gradually extending. It may now be said to be universal in the cities and towns of Europe; it is making rapid progress throughout America, where it has long been used in the principal cities of the United States and of Canada. Its introduc tion into Asia has been more recent, and its progress there. as might have been expected, is much slower. It has also been introduced into the principal towns in Australia and Tasmania.
From 1658 to 1739, the attention of men of science in England had been repeatedly turned to the streams of inflammable air issuing from wells and mines in the coal dis tricts, various communications on the subject having been read before the royal society of London. In the last-mentioned year, the Rev. Dr. John Clayton, dean of Kildare, gave an account of experiments in which he had distilled gas from coal,_ It was not, however, till 1792 that the possibility of applying gas, distilled from coal, to the pro duction of artificial light was demonstrated. In that .year, Mr. William Murdoch con structed apparatus by which he lighted his house and offices at Redruth, in Cornwall. In 1798, he lighted part of the manufactory of Messrs. Bolton and Watt at Soho; and in 1605 he lighted the cotton-mills of Messrs..Phillips and Lee at Salford: A proposal was made by M. Le Bon to light a portion of Paris with gas in 1802: In the succeeding year, Mr. Winsor commenced lecturing on the subject in London. He being a man of a sanguine and enthusiastic temper, his strong statement& probably tended to retard rather than advance the new art.. He promised to every depositor of £5 an income exceeding SZ00 per annum, and he urged the government to take the matter into their own hands, as a certain means not only of clearing off the national debt, but of securing a permanent and large revenue to the country. The chartered gas company of London, which was the first company incorporated, obtained their act of parliament in 1810. At that time; Mr. Winsor, who had been instrumental in establishing the company, was employed by them; but in 1813 they found it necessary to engage the late Mr. Samuel Clegg, who, from the year 1805, had been engaged in promoting the use of gas, and to whose ingenuity scientific skill the .chartered company, as well as the community, were greatly indebted. Mr. Clegg was the inventor of the hydraulic main, of the wet lime purifier, and of the wet gas-meter, all which were essential to the success of gas lighting.
As the first gas applied to artificial lighting was obtained from coal, so, owing to the economy attending its manufacture, the use of any other material only occurs when coal cannot be obtained except at an exorbitant price, and where other gas-yielding mate rials are unusually cheap. Resin and 'oils are the best substitutes for coal. Many
schemes have recently been started for supplanting coal-gas by air charged with vapor of volatile hydrocarbon fluids, such as petroleum spirit; also for improving coal-gas. and rendering hydrogen gas, derived from water, suitable for illuminating purposes. None of these has as yet attained such success as to enter into permanent competition with coal gas; but some of them are used in large hotels iu America, and by other large estab lishments in localities where coal-gas is not easily procured.
Destructive distillation by the action of heat is in all cases tke means employed to disengage the gas from coal. The manufacture of coal-gas is likely to continue the most general process for producing artificial light; and the modes of storing, distributlpg, and using the various substitutes which have been proposed, being similar to those applied to coal-gas, it is unnecessary to enter into details with regard to them.
As a branch of manufacturing industry, coal-gas-works occupy an important position, not only from the immense capital permanently embarked, and the great number of hands employed in them, but also from the_ demand created bythem for coal, lime, etc., and for iron-work, brass-work, and gas-meters. In London alone, the aggregate share and borrowed capital of the nine companies supplying the metropolitan district amounts to nearly nine and a half millions sterling. The success of recent methods of applying the electric light has seriously depreciated the value of shares in gas companies. In England, there are above 400 gas companies; in Scotland, above 180; in Ireland, above 60, besides about 130 gas-works belonging to individuals or corporations. The coals best adapted for the manufacture of gas are those called in England cannel coals, and in .Scotland parrot coals. The English caking coals, mostly got near Newcastle-on-Tyne, are, however, from their cheapness and the superior quality of the coke which remains after distillation, more extensively used than any other. In Scotland, parrot coals, till the recent changes in the coal-trade, were used exclusively. Cannel is used extensively in Liverpool, Manchester, and some other towns; a proportion of cannel or of Scotch parrot- is used with caking coal in London, Dublin, and other places to improve the quality of the gas, but in England generally the gas is made from caking coal. The coke of the English cannel coals is of fair quality, though inferior to that of the caking coals. The coke of the Scotch parrot coals is very inferior, that of some being alto gether worthless.