90 THE CANADIAN NATURALIST. [Vol. X. 



1. Color 1 



2. Odor -5 



3. Chlorine 1-0 



4. Phosphates none. 



5. Nitrates none. 



6. Ammonia -5 



7. Albumenoid 1-0 



8. Oxygen absorbed 2-0 



9. Hardness 1-0 



10. Solids in solution 1-0 



1 1 . Solids in suspension 1-0 



12. Microcosms 1-0 



10-0 



This water, therefore, stands very high on the British scale of 

 purity. Some other examples of Ottawa water ranged as high 

 as 12 for impurity but 11 may be taken as the mean value. 



Now by the publication of these monthly returns based upon 

 the same methods, I am enabled to give a comparative view of a 

 series of English water supplies examined in the same month of 

 September last. Thus — all exceptionally pure : 



Rochdale valuation := 9 



Warwick = 10 



Canterbury ::= 12 



Swansea and Wolverhampton := 15 



First class : 



Bolton = 17 



Shrew^sbury := 19 



Brighton and Salford = 21 



Exeter and Leicester := 23 



Bury and Edinbro' = 24 



Poi'tsmouth = 27 



Plymouth = 28 



Birmingham = 29 



Bristol and Whitehaven =: 30 



London supplies 21 to 39 



Second class : 



Rugby = 46 



Liverpool = 47 



Darlington = 50 



Newcastle-on-Tyne = 68 



Kings and Lynn = 110 (condemned.) 



Ottawa supply 10 to 12 



