226 
TYPHOID FEVER IH DISTRICT OF COLUMBIA. 
FEASIBILITY AND PROPRIETY OF FILTERING THE WATER SUPPLY 
OF WASHINGTON, D. C.a 
This document contains a valuable report by Lieut. Col. A. 
^Miller, Corps of Engineers, L^. S. Army, upon the question of the 
Potomac River water and its relation to typhoid fever. 
Chemical and bacterial analvses of the river water are given and 
the results of preliminary experiments vdth the English or slow sand 
filters and the American or mechanical filters are described. The 
recommendation is made that for the filtration of the Washington 
water supply the American or mechanical system of filtration be 
adopted. 
The document also contains a report by !Mr. E. D. Hardy, covering 
the performance of the experimental filters in detail. 
It also contains a report by Mr. Robert Spurr Weston, giving the 
character and composition of Potomac River water, especially after 
subsidence in the system of reservoirs. Much valuable bacterio- 
logical and chemical data are summarized and the various systems 
of filtration as applied to the Potomac water compared. ^Ir. Weston 
concludes that the English system can be adapted to the clarification 
and purification of the Potomac River water by adding a coagulant 
to the water at times when the Potomac water, after subsidence in 
the system of reservoirs, would contain more than 15 parts of sus- 
pended matter per million. 
The American system can be adapted to the clarification and 
purification of the Potomac River water by arranging for periods of 
coagulant and supplementary subsidence before filtration. 
Both systems would, therefore, certainly improve the Potomac 
River water after subsidence in the system of reservoirs, and the 
choice between them depends entirely upon the comparative cost. 
POLLUTION OF THE POTOMAC RIVER AND ITS RELATION TO THE 
WATER SUPPLY OF THE DISTRICT OF COLUMBIA. 6 
[By Marstiall O. Leighton, United States Geological Surrey (1900).] 
The author states it as a general law that while a drainage area is 
inhabited the water of a river will inevitably be polluted, the damage 
increasing as the population increases. 
Referring to the Potomac River, he considers it grossly abused. 
Foul and putrid matter is deposited in the main stream and its tribu- 
taries apparently without regard to the effects upon the interests 
« Letter from the Secretary of War, transmitting copy of a communication from the 
Chief of Engineers, Lmited States Army, submitting report of an investigation of the 
feasibility and propriety of filtering the water supply of the city of Washington. 56th 
Cong., 1st sess., S. Doc. Xo. 259. [Alarch, 1900.] 
& S. Doc. 181, March 1, 1905. 
