XI, B, 2 



Gabel: Examinations of Swimming Pools 



79 



Table XII. — Average bacterial counts of pools — Continued. 



37° INCUBATION. 



Table. 



Monday. 



Tuesday. 



Wednes- 

 day. 



Thursday. 



Friday. 



Saturday. 



11 



4,025 



28,900 



8,000 



9,600 



6,300 



750 



200 



41,500 



2,400 



800 



200 



360 



2,420 



537 



37,260 



18, 500 



28,500 



100 



5,300 



19,000 



5,100 



315 



5,500 



121,300 



9,000 



91,300 



250,000 



65,000 



90 



600 



10,000 



7,100 



1,555 



58,600 



142,000 



29,000 



2,060,000 



3,350,000 



193,330 



160 



2,935 



4,000 



2,000 



14,300 



66, 600 



422, 600 



1.433,300 



460,000 



6,600,000 



300,000 



430 



5,800 



34,000 



80 



6,690 



846,600 



160,000 



147,000 



256, 560 



18,000,000 



1,040,000 



253 



450 



42,000 



20 



22. 195 



III 



IV. 



V . 



VI 



VII 



VIII 



IX - 



f I 



^\ll 



XI 



Averagre 



9,334 



10,672 



50,131 



441,484 



848, 136 



1,864,916 





Table XIII. — Summary of tests for 



Bacillus colt 



in 



swim,ming-pool waters. 



Table. 



Disinfectant used in pool. 



Bacillus coli, times present 

 during one week. 



Kind. 



Quantity 

 (parts per 

 million). 



Frequency. 



Pool I. 



Pool II. 



Pool III. 



1 

 Average. 



•H 



6 

 o 



s 





S 



i 



i 



o 





8 



O 



i-H 



I 



II 



III 



IV 



V 



VI 



VII 



VIII 



IX 



X 



X 

 XI 



Calcium hypochlorite 





Twicea 



week. 

 Weekly... 



do 



....do 



....do 



....do-.... 



2 



1 





 

 

 



1 

 



1 



2 







4 



4 

 4 



3 

 2 

 4 



1 



1 



2 

 3 







1 





 

 

 



1 



4 



4 

 3 

 2 

 

 3 



5 



1 



2 

 

 

 

 

 



2 







2 



4 

 4 

 2 

 

 2 

 3 



2 







2.23 



1 



0.66 















0.66 







2.5 







2 

 0.5 



3.33 



4 



3.66 



2.33 



0.66 



3 



2 



2.6 







2 

 3 



Chlorine from calcium hypo- 

 chlorite. 



do 



do 



Copper sulphate 



0.5 



1.0 

 2.0 

 1.0 

 2.0 



do 



None 



Chlorine from calcium hypo- 

 chlorite. 



Chlorine from calcium hypo- 

 chlorite (2d week). 



Chlorine from calcium hypo- 

 chlorite. 



Chlorine from antiformin 



Chlorine from calcium hypo- 

 chlorite. 



0.5 

 0.5 

 0.5 



0.25 



Daily 



—-do 



- do 



....do 



...-do 







— - 



— - 







1 



3 







DISCUSSION OF TABLES 



A study of the preceding tables shows the relative restraining 

 effects on Bacillus coli of the different disinfectants used. 

 During week I calcium hypochlorite was used, in the same 

 manner as used previous to these tests, but the strength of the 

 disinfectant was low, and adequate purification was not effected. 

 During week II, when, at the beginning of the week, 0.5 part of 

 available chlorine by chemical analysis per million parts of 

 water was added in the form of calcium hypochlorite, the B. coli 



141844 2 



