CHEMICAL EXAMINATION OF THE WATEK SUPPLY. 281 
found the greater number of these waters to contain large amounts 
of chlorine and nitrates; if anything, somewhat larger amounts than 
have been found by Longley, Lynch, and myself in the waters of 
such shallow wells as are in use to-day. He arrived at the conclusion 
that only 27 per cent of these waters were ‘^passable,’’ the remainder 
being polluted. 
We have included also in our tables the results of the analyses 
made by these several chemists, to whom due acknowledgment is 
hereby made, and any conclusions which have been arrived at 
respecting the pollution of any of these water supplies have been 
reached from a study of all of the analytical data available at the 
present time. 
The results of our analyses, together with those obtained by other 
investigators, are given in the following tables: 
Number of table. Subject of table. 
1 and 2 
3, 4, and 5. 
8 
9, 10, 11, and 12 
13 
14 
15 
16 
17 
18, 19, 20, 21, 22, and 23. 
24 
25 
26 
The waters of the reservoirs and storage basin. 
Analyses of the water of the Potomac River. 
Analyses of the waters of several American rivers. 
Taps and hydrants. 
Analyses of the waters of deep wells in the District of Columbia. 
Analyses of the waters of shallow wells in the District of Columbia.^ 
Condition of shallow wells as shown by chemical analysis. 
Condition of shallow wells as shown by the bacteriological examination. 
List of shallow wells regarded as unfit for drinking purposes. 
Summary of results of analyses of the water of the reservoirs and storage 
basin. (July to October, 1906.) 
Summary of Longley’s analyses of the water of the reservoirs and storage 
basin. (February to June, 1906.) 
Chemical purification of Potomac water due to subsidence and filtration. 
The composition of tap water as compared with the waters of the Dalecarlia 
reservoir, inlet, and the storage basin. 
Analyses of tap water, compared for different short periods, during the sum- 
mer of 1906. 
Analyses of tap water supplied the city of Washington, during the summer of 
1904 and 1906. 
Results of analyses of miscellaneous water supplies: 
(1) The Government Hospital for the Insane (St. Elizabeth’s). 
(2) The Soldier’s Home. 
(3) Chevy Chase. 
Chemical analyses and results of bacteriological examination of table waters.^ 
Chemical analyses and results of bacteriological examination of ice sold in the 
District of Columbia. & 
Chemical analyses of ice manufactured in the District of Columbia, by Doctor 
Lynch. 6 
Chemical analyses and results of bacteriological examination of wells in use 
in ice factories in the District of Columbia. 6 
o In Tables 8, 9, 10, 11, and 12, the results given immediately following the laboratory number of the 
given well are our own. Those marked “L” are the results of Longley’ s analyses, those marked “Ly” 
were obtained by Lynch, and those marked “R” were obtained by Clifford Hichardson. 
b Given in other sections of the report. 
