WORLEY : A SEPTIC TANK. 



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being designated as I, II, and III, respectively. Collections 

 were made on Mondays, at twelve noon and live p. m. ; on 

 Wednesdays and Fridays, at eight a. m., twelve noon, and five 

 P. M. Each sample contained one liter, which was taken di- 

 rectly to the laboratory and divided into two parts. That part 

 to be used in determining the ammonias and the oxygen con- 

 sumed was sterilized with 4 c. c. of a solution of one part sul- 

 furic acid and three parts water ; that part from which the other 

 determinations were to be made was sterilized with 4 c. c. of a 

 solution of one part formaline and three parts water. This 

 method of sterilization was found to be perfectly satisfactory. 

 The corresponding parts of each sample taken during the day 



