Gas leakage.
--In a report of the New River Water Company, Professor Spencer, in speaking of the corrosion of iron mains and the effect of gas leakage, states that it is computed that there are 4,000 miles of gas mains laid under the roadways of London, from which 600,000,000 feet of gas are annually absorbed into the earth, the far larger proportion of which could be saved by improved condults. As a matter of economy, its results would pay a dividend of five per cent. on the gross capital of the London companies. It is a question for photographers, how far the extraordinary excess of carbureted hydrogen, with its other impurities, contaminating their waters at times, may account for exceptional and unexplainable phenomena and puzzling failure.