Still, industrial cases of poisoning in gas works are recorded. Of these the most important will be mentioned. Six persons were employed in a sub-station in introducing a new sliding shutter into a gas main, with the object of deviating the gas for the filling of balloons. A regulating valve broke, and the gas escaped from a pipe 40 cm. in diameter. Five of the men were rendered unconscious, and resuscitation by means of oxygen inhalation failed in one case. In repairing the damage done two other cases occurred.[8] In emptying a purifier a worker was killed from failure to shut off the valve. Besides poisoning from illuminating gas, industrial poisoning in gas works is described attributable, in part at least, to ammonia. Thus the report of the factory inspectors of Prussia for 1904 narrates how a worker became unconscious while superintending the ammonia water well, fell in, and was drowned. A further case is described in the report of the Union of Chemical Industry for 1904. In the department for concentrating the gas liquor the foreman and an assistant on the night shift were getting rid of the residues from a washer by means of hot water. The cover had been removed, but, contrary to instructions, the steam had not been shut off. Ammonia fumes rushed out and rendered both unconscious, in which condition there were found by the workmen coming in the morning.[9] In the preparation of ammonium sulphate, probably in consequence of too much steam pressure, gas liquor was driven into the sulphuric acid receiver instead of ammonia gas. The receiver overflowed, and ammonia gas escaped in such quantity as to render unconscious the foreman and two men who went to his assistance.[10] The use of illuminating gas in industrial premises can give rise to poisoning. Thus the women employed in a scent factory, where so-called quick gas heaters were used, suffered from general gas poisoning.[11] In Great Britain in 1907 sixteen cases of carbonic oxide poisoning from use of gas in industrial premises were reported. COKE OVENS