XI. A, 3 Heise and Aguilar: Purification of Swimming Pools HI 



was not irritating to the eyes. Unfortunately the author gives 

 no data concerning the chemical quality of the water used nor 

 the exact strength of hypochlorite employed. The water was 

 filtered and refiltered, and alum was used as coagulant. As the 

 author points out, the coagulation with alum and subsequent 'fil- 

 tration removes the carbonates and bicarbonates which would 

 otherwise hinder the action of copper sulphate. 



Our results with copper sulphate show clearly the unsuitability 

 of this method to a water high in substances which react with a 

 copper salt. The test was conducted for two weeks, 1 part of 

 crystalline copper sulphate per million parts of water being 

 employed during the first week and 2 parts per million (with 

 fresh water) during the second. In neither case was an effect 

 on the bacterial content apparent after the first day, and long 

 before the end of the week the colony count had reached an 

 enormous figure, the copper sulphate seemingly exercising not 

 the slightest inhibiting effect. 



The chemical analysis of the water showed little or no varia- 

 tion (Tables III and IV). Upon addition of copper sulphate the 

 turbidity of the water increased greatly, owing to interaction 

 with the bicarbonates present and subsequent precipitation 

 of hydroxides and carbonates of copper, calcium, or magne- 

 sium. This action would account for the removal of copper 

 sulphate and its failure as a germicide in this series of tests. 

 Owing to the turbidity resulting from its use and to the lack of 

 efficient sterilizing action, it is apparent that, without filtration, 

 the use of copper sulphate is not to be recommended for water 

 similar to the one under observation. 



A number of attempts were made to secure adequate purifi- 

 cation with chloride of lime, different quantities being used each 

 week. 



The first attempt with chloride of lime was made with an 

 addition of 0.5 part of available chlorine * per million parts of 

 water. The effect on the bacterial content was apparent for 

 only one day, after which the count was excessive and B. coli 

 appeared. No better results attended the addition of 1 part 

 per million, and only with an addition of 2 parts per million could 

 an appreciable effect on the bacterial content on the second day 

 be ascribed to the chemical added. After the second day the 

 bacterial increase proceeded unchecked. In none of these cases 

 was the effect on the chemical constituents great enough notice- 



*A11 hypochlorite used was analyzed with arsenious acid, using starch- 

 potassium-iodide paper as indicator. 



