CHEMICAL EXAMINATION OF THE WATER SUPPLY. 293 
ply in itself, which must be properly safeguarded by constant inspec- 
tion and numerous bacteriological and chemical examinations. It 
is evident, therefore, that while they supply a considerable number 
of persons vdth cool, palatable drinking water they are constantly 
subject to sewage pollution, and serve to greatly increase the com- 
plexity of a situation in public sanitation already exceedingly 
complex and difficult to control. - 
TABLE WATERS. 
As already stated, our investigation has included the bacterio- 
logical and chemical examination of a number of table waters used 
for drinking purposes throughout the District of Columbia. Chem- 
ical anal 3 ^ses of 20 of these waters have been made, the results of 
which are given in a table, page 163, of this report.® It will be 
seen from an examination of this table that the greater number of 
these waters showed no chemical or bacteriological evidences of 
pollution, and probabl}^ the greater number- of them are pure and 
wholesome waters. Those showing no chemical evidences of pollu- 
tion are as follows : 
Laboratory 
No. 
238. Pure table water. 
357. Gitche Crystal Spring water. 
384. Arlington filtered water. 
420. Takoma Spring water. 
421. Magnolia Spa water. 
429. Powhatan Spring water. 
447. Castalia Spring water. 
457. Great Bear Spring water. 
458. F. H. Finley & Son’s distilled water. 
.461. Sparkling Rock Spring lithia. 
462. Arlington Springs mineral water. 
463. Sprudel Wiesbadner wasser. 
' 471. Poland water. 
Of these waters showing no chemical evidences of pollution. Nos. 
458, 461, and 471 contained a large number of bacteria per cubic 
centimeter, which in the case of 458 and 461 is probably to be attrib- 
uted to carelessness in the handling and bottling of these waters, 
inasmuch as No. 458 is a distilled water and No. 461 is a manufactured 
lithia water made by a local firm, probably from tap water by the 
addition of the necessary saline ingredients. 
« Fom’ of these waters, viz, Gitche Crystal Spring water, Powhatan Spring water, 
Great Bear Spring water, and Poland water were analyzed in 1905 by Haywood and 
Smith. See Bulletin No. 91, Bureau of Chemistry, U. S. Department of Agriculture. 
