266 THE SANITART DISPOSAL OF SEWAGE. 



communities, and quite generally by the scattered rural 

 population, were condemned as being unsanitary in 

 principle and the fruitful sources of the contamination 

 of domestic water supply 1 



With the growth of large cities in Europe and America 

 came the problems of sewage disposal and the necessity 

 for avoiding the pollution of rivers and streams. Much 

 time was devoted to a description of modern methods, 

 consisting principally of disinfection, chemical precipi- 

 tation, underground disposal with, incidental aeration, 

 and filtration through broad areas. The latter is ap- 

 proved as the system offering the best results at the least 

 expense, wherever local conditions are favorable thereto. 

 As illustrations, the systems in successful operation in 

 Berlin, Paris and other European cities, and in this 

 country at South Framingham, Lawrence, Brockton, 

 Marlboro, Gardner and Amherst, Mass., were cited. 

 This system consists in collecting, through ordinary 

 sewers, all town sewage at a given point, and pumping 

 it thence (or allowing it to flow by gravity), to fields of 

 gravelly or sandy soil, where it is allowed to flow over 

 the surface and filter gradually through the soil. By 

 having several fields the operation can be made intermit- 

 tent, and a comparatively small area suffice for the re- 

 ception and disposal of a large amount of sewage for an 

 almost indefinite period. 



A history of the treatment of sewage at Yassar College 

 was given, to which was added a description of the 

 methods at present employed. Heretofore the sewage 

 was filtered imperfectly through tanks of muck and 

 gravel, and the final effluent discharged into a small 

 stream flowing through the college grounds ; thence into 

 the Hudson River at a point some six miles distant. 

 During the summer of 1895 a farm of two hundred acres 

 adjoining the college property was purchased, and a sys- 

 tem of intermittent filtration installed. All sewage from 



S04: 



