Montreal Drinking Water. 1^8 



carbonates giving temporary and sulphates permanent 

 hardness. Where the hardness of a water is considerable, 

 it is often important to distinguish between that which is 

 permanent and that which is only temporary ; but where 

 the hardness is low, as in Montreal water, such a distinc- 

 tion is, from an economical or hygienic point of view un- 

 necessary. 



Like the chlorine and solids and usually with them, the 

 hardness fluctuated, but, as necessitated by the small pro- 

 portion of solids, it was never large. The average for the 

 period covered by my determinations was 4.63, a low 

 result and one showing our water to compare favorably 

 with that of other towns. The maximum was 6.7 on 

 Feb 11th and the minimum 3.2 on January 12th. 



NITROGEN. 



The average quantity of nitrogen, estimated as ammonia, 

 during January, February and March 1886 was 0.0031 1 

 parts free and . 0194 parts albuminoid ammonia per million, 

 the maximum and minimum for free ammonia being res- 

 pectively 0.004 on several occasions and 0.0009 on March 

 4th, and the corresponding figures for albuminoid ammonia 

 0.03 on January 18th and 0.01 on February 25th. 



FLUCTUATIONS. 



The analyses showed from day to day and week to week, 

 as was to be expected, certain variations in hardness, 

 chlorine, residue &c, dependent chiefly upon the dilution 

 of the water by rain and snow and the relative heights of 

 the Ottawa and St. Lawrence. 



These fluctuations were noteworthy in that the maximum 

 was in every case more than double the minimum. 



Maximum. Minimum. Ratios. 



Chlorine.... 0.40 0.175 2.28 to 1 



Hardness... 6.70 3.20 2.09 to 1 



Residue.... 9.30 4.06 2.29 to 1 



J Or 0.0035 if the doubtfully high result for Feb. 18th (0.0074) 

 be considered in striking the average. 



