Special Article.

THE PURIFICATION OF WATER SUPPLIES BY SLOW SAND FILTRATION.  (Continued from page 911.)III.WATER FILTRATION IN THE UNITED STATES (CONTINUED).B. THE ALBANY FILTRATION PLANT.The Albany plant is the largest of its kind now in operation in this country and also deserves consideration from the fact that the best and most modern experience was utilized in its construction. The sanitary results flowing from the operation of this filter are especially noteworthy since before filtration the water had proved highly injurious to the public health.The city of Albany, N. Y., with a population of about 100,000, is situated on the Hudson river about eight miles below the mouth of the Mohawk. The total urban population in 1900 on the watershed above Albany was about 376,000 and, including the rural population, amounted to 80 per square mile, or somewhat less than the number on the Merrimac watershed above Lawrence