experimental tar-kiln was erected near the Abbey, and here coal-gas became accidentally employed in illumination. Having noticed the inflammable nature of a vapour arising during the distillation of tar, the Earl, by way of experiment, fitted a gun-barrel to the eduction pipe leading from the condenser. On applying fire to the muzzle, a vivid light blazed forth across the waters of the Frith, becoming, as was afterwards ascertained, distinctly visible on the opposite shore.”

A few years later the foundation of the coal-gas manufacture was laid by William Murdoch, a Scotchman, who must be credited with the practical introduction of this illuminating agent. The idea had about the same time occurred to a Frenchman, Lebon, but in his hands the suggestion did not take a practical form. Murdoch was overseer of some mines in Cornwall, and in 1792 he first lighted his own house at Redruth. He then transferred his services to the great engineering firm of Boulton and Watt at Soho, near Birmingham, where he erected apparatus in 1798, and in the course of a few years the whole of this factory was permanently lighted by gas. From this time the introduction of gas into other factories at Manchester and Halifax was effected by Murdoch and his pupil, Samuel Clegg. From single factories coal-gas at length came into use as a street illuminant, although somewhat tardily. Experiments were made in London at the Lyceum Theatre in 1803, in Golden Lane in 1807, and in Pall Mall two years later.

It was fifteen years from the time of Murdoch’s first installation at Soho before the streets of London were lighted by gas on a commercial scale. Our grandfathers seem to have had a great dread of gas, and public opposition no doubt had much to do with its exclusion from the metropolis. There were even at that time eminent literary and scientific men who did not hesitate to cast ridicule upon the proposal, and to declare the scheme to be only visionary. But about 1806 there came into this country an energetic German who passed by the name of Winsor, and who is described as an ignorant adventurer, whose real name was Winzler. Whatever his origin, he certainly helped to rouse the public interest in gas lighting. He took out a patent, he gave public lectures, and collected large sums of money for the establishment of gas companies. Most of the capital was, however, squandered in futile experiments, but at length in 1813, Westminster Bridge, and a year later St. Margaret’s parish, was successfully lighted. From that period the use of gas extended, but it was some time before the public fears were allayed, for it is related that Samuel Clegg, who undertook the lighting of London Bridge, had at first to light his own lamps, as nobody could be found to undertake this perilous office. Even after gas had come into general use as a street illuminant, it must have found its way but slowly into private houses. In an old play-bill of the Haymarket Theatre, dated 1843—thirty years after the first introduction into the streets—it is announced—

“Among the most important Improvements, is the introduction (for the first time) of Gas as the Medium of Light!”

The manufacture of coal-gas, first rendered practicable by the energy and skill of the Scotch engineer Murdoch, is now carried on all over the country on a colossal scale. It is not the province of the present volume to deal with the details of manufacture, but a short description of the process is necessary for the proper understanding of the subsequent portions of the subject (see Fig. 3). The coal is heated in clay cylinders, called retorts, provided with upright exit pipes through which the volatile products escape, and are conducted into water contained in a horizontal pipe termed the “hydraulic main.” In the latter the gas is partially cooled, and deposits most of the tar and watery liquor which distil over at the high temperature to which the retorts are heated. The tar and watery liquor are allowed to flow from the hydraulic main into a pit called the “tar well,” and the gas then passes through a series of curved pipes exposed to the air, in which it is further cooled, and deposits more of the tar. From this “atmospheric condenser” the gas passes into a series of vessels filled with coke, down which a fine spray of water is constantly being blown. These vessels, known as “scrubbers,” serve to remove the last traces of tar, and some of the volatile sulphur compounds which are formed from the small quantity of sulphur present in most coals. The removal of sulphur compounds is a matter of importance, because when gas is burnt these compounds give rise to acid vapours, which are deleterious to health and destructive to property.