XI, B, 2 



Gabel: Examinations of Swimming Pools 



73 



for this work and also supplied the data under "Turbidity" 

 given in Table XIV. 



In order to study the effect of various disinfectants on 

 sw^imming pools, the chemical additions recorded in Table D 

 were made. The Roman numerals refer to the tables of bacter- 

 iological data in which the results of the additions enumerated 

 are recorded. 



Table D. — Outline of tests on Manila swimming pools. 



Week. 



Disinfectant. 



Results 



in 

 Table— 



Kind. 



Quantity 



(parts 



per 



million). 



Added- 



1915. 

 Aue 30 to Sent 4 



Chloride of lime 





Twicea week 



Once a week 



do 



I 



II 



III 



IV 



V 



VI 



VII 



VIII 



IX 



X 



XI 



Sept 20 to 25 



do 



«0.6 



•1.0 



•2.0 



1.0 



2.0 



0.0 



•0.5 



• 0.5 



•0.26 



•0.25 



Sept 27 to Oct 2 



do - 



Oct 4 to 9 



do 



do . 



Oct. 11 to 16 



Copper sulphate 



■. .do 



do — 



Oct. 18 to 22 



do . 



Oct. 25 to 30 - - 







Nov. 1 to 8 . . 



Chloride of lime 



do 



Daily. 



Nov. 8 to 13i> :. 



do 



Nov. 15 to 20 - 



Chloride of lime or 



antiformin. 

 Chloride of lime 



do 



do 



Dec 6 to 11 







• As available chlorine. 



* Without change of water. 



Table I. — Calcium, hypochlorite added twice a week to water in swim,ming 

 pools, week of August 30 to September U, 1915. 



[Bacteria 



per cubic centimeter of water.] 









Aug. 30. 



Aug. 31. 



Sept. 1. 



Sept. 2. 



Sept. 3. 



Sept. 4. 



Pool I: 



Agar. 25° - 



21,600 

 57,000 

 50.000 



2,000 

 2,500 

 1.400 



2,100 

 3.800 

 5,600 



5,000 

 700 

 600 



3,000 

 100 



loa 



1.000 

 4.300 

 2.100 



Litmus lactose agar, 37° C 



Congo red agar. 37° C 





43,000 



2,000 



3,800 



2.800 



1.100 



2,200 



Pool II: 



Agar. 25° C 



69.000 

 110,000 

 100,000 



4,800 

 4,700 

 3.300 



6.800 

 2,200 

 4,100 



1,000 

 600 

 700 



400 

 300 

 100 



600 

 3,600 

 4,100 



Litmus lactose agar, 37° C 



Congo red agar, 37° C 





93, 000 



4.300 



4.000 



800 



270 



2,700 



Pool III: 



Agar, 25° C 



2,900 

 3,000 

 5,000 



2,000 

 2,700 

 2,100 



7,000 

 8,000 

 3,200 



5.000 

 600 

 800 



200 



900 

 800 





Litmus lactose agar, 37° C 



Congo red agar. 37° C 







Average 





8,600 



2.300 



4,800 



2,100 



600 









