FILTRATION IN LONDON.
System Pursued in the British Metropolis.
The Thames is the source of supply to six out of the eight London water companies. The Kent company derives its water altogether from chalk beds; the New River, from a spring, the river Lea,and thirteen chalk wells. The six which furnish Thames water supply it in a filtered state—the process of filtration employed being sand. The sandbeds used have a maximum thickness, varying according to locality. That of the Chelsea company’s bed is four feet, six inches ; of the East London,only two feet, six inches. The accompanying views, showing part of the filtration plant of the East London Water company, were taken, with others, by Mr. Allen Hazen during a European tour.