THE PURIFICATION OF WATER SUPPLIES BY SLOW SAND FILTRATION.
(Continued from page 853.)II.
WATER FILTRATION IN THE UNITED STATES.
The first sand filter constructed in the United States was the one built in 1872 under the direction of Mr. J. P. Kirkwood at Poughkeepsie, N. Y. A similar filter was installed by the same engineer at Hudson, N. Y., in 1874. Both these plants are still in operation. Although a beginning in water purification in this country was made at this early date, a more decisive step was taken by the construction of a sand filter at Lawrence, Mass., in 1893. The establishment of this filter may be said to mark the opening of the modern era in water purification in America. One of the leading American authorities on water supply has said:The Lawrence filter was in a large sense the beginning of water purification in America. This