An explosion of gas of a magnitude unprecedented in the history of gas illumination occurred in London, July 5. The district in which the disaster happened had been supplied with gas through a system of small (three and four inch) mains, which had become inadequate. Accordingly preparations had been made to increase the supply by laying down a new thirty-six inch truck main. The work had nearly been completed, only a single length of pipe having to be put down before the gas could be turned in. The point of junction was in an open trench, where the end of the main had been plugged and fitted with a half-inch stand-pipe.

Just before the explosion workmen had been engaged in cutting out the plug from the end of the pipe. The foreman was standing on the main near the stand-pipe, from which he had removed the pressure gauge with which he had tested the mam, and Ascertained that there was no pressure in it. He then smelt the stand-pipe to ascertain whether any gas was issuing therefrom, and finding none came out, he applied a light, and almost immediately a dull rumbling sound was heard, followed by an explosion, which blew one of the workmen a considerable distance into the open pipe on the opposite side of the trench, killing him instantly, and so injuring the other man that he died shortly after his removal to the hospital. The foreman escaped unhurt. There was a quantity of dust and smoke, but no flame was seen.

Almost simultaneously another explosion occurred some yards away, and was followed by five or six more explosions at varying distances along the line of the main. The streets were much torn up, many buildings were wrecked or more or less seriously injured, and several persons were hurt. At the second point of explosion something like a dozen lengths of main were upheaved ; at others, from three to six lengths were blown out; while in two places the explosion was limited to one length. At each point of explosion the paving stones were hurled into the air, causing great destruction of surrounding property, and peril and injury to passers-by.

At the coroner’s inquest, the foreman of the pipe-layers testified that the point of first explosion was nearly two miles from the “ live main containing gas. The new main—technically “ dead ” main—was shut off from the live main by means of a valve and cap, the cap being bolted on so that there was no flow of gas from the live main to the dead one. Everything was ready, however, to turn the gas into the new main when the lacking length at the west end had been laid. How the gas got into the mains which was broken up is a mystery. In his testimony, the chief inspector of the gas company said:

“ I was certainly not aware of there being gas in the main ; but it did not occur to me to test it. I did not think gas had come there. The valve in Howland street was put in under my superintendence, and I know that it was sound and proper. 1 have no doubt that the explosion was caused through there being gas in the main to the westward. About five per cent of gas combined with atmospheric air would be sufficient to create an explosive mixture, but ten per cent would be more dangerous. The main had not been tested with a view to seeing whether gas was present. It is my belief that gas had got mixed with the air in the main, but I cannot account for it. The theory I have formed is that gas must have escaped from a fracture in one of the smaller pipes, and found its way into the main.”

Another theory was that the passage of some heavy vehicle over the valve in Howland street might have loosened it enough to let a sufficient quantity of gas into the “dead ” main to make the mixture of gas and air explosive. The explosion not only tore up the streets in places, but broke in the sewers, and so damaged the gas and water connections of the houses as to leave the district for some hours without water or light.

Though this accident was pronounced unprecedented by gas engineers, it was quickly followed by a similar but fortunately less disastrous one of the same sort. A number of workmen were engaged in enlarging a gas main at Bilston, near Wolverhampton, England, when, through an incautious use of a light, an explosion occurred, and a portion of the roadway and pavement was upheaved. The explosion traveled underground, and burst at some distance from its origin. I he amount of damage done, however, was not great, and no lives were lost. A second explosion occurred some hours after the first.

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