PURIFICATION OF WATFiR FOR DRINKING PURPOSES 129 



' From the theoretical considerations here instituted, 

 it would be anticipated, therefore, that, dealing with the 

 same raw material, the West Middlesex Company should, 

 on the whole, obtain the best average result, from a 

 biological point of view, and that the results obtained 

 by the other four companies would follow in the order 

 of Chelsea, Southwark, Grand Junction, and Lambeth.' 



In putting the above statement, which was made 

 in the year 1886, to the test of the experience gained 

 during the whole of the three years 1886, 1887, and 

 1888, over which our systematic investigations ex- 

 tended, it is found that the several companies stood as 

 follows : — 

 Average number of Micro-organisms found i7i 1 c.c. of Thames 

 Supplies delivered in London 



Thus the average results t^ken over the three years 

 are almost in complete harmony with theoretical antici- 

 pations, the only discrepancy (which admits of a ready 

 explanation) being that the Lambeth Company is out of 

 place with regard to the Southwark and Grand Junction 

 Companies. 



We may, perhaps, compare the results achieved by 

 the several companies more satisfactorily by arranging 



K 



