Chemical Composition of the Thames Water. 



121 



From which the following average composition may be de- 

 duced : — 



Table VI. — Average Composition of the Thames Water at 

 Chelsea during the year. 



Suspended matter 



Organic 



Inorganic 



Dissolved matter :- 



Organic 



Inorganic 



Chlorine 



Sulphuric acid ... 



Lime 



Hardness 



Maximum. | Minimum. 



Mean. 



In grains in the gallpn. 



11-247 

 38-107 



1-60 

 40-62 

 1114 

 3-489 

 8-719 

 13°-5 



7-423 

 22-73 



116 

 36-62 

 6-403 

 3-225 

 8-196 

 12°-7 



The following points cannot fail to be remarked in considering 

 these numbers : — 



1st. The very much greater variations in the composition of 

 the water here than at Kingston. 



2nd. The great decrease in impurity generally, but especially 

 in the suspended matter which takes place during the winter, 

 and increase in the summer, above the mean for the whole year. 



3rd. The extraordinary fluctuations in the quantity of common 

 salt present, the chlorine varying from 11*14 grs. in the gallon 

 in September 1855 to 1*667 in December of the same year. 



4th. That the amounts of sulphuric acid, and of lime and 

 magnesia salts, remain, however, much more constant. 



But in order to present in the most striking form the supe- 

 riority of the water at Kingston over that at Chelsea as a source 

 for the supply of London, I have drawn up the following Table, 

 exhibiting a — 



Table VII. — Comparison of the Mean Annual Composition of 

 the Thames Water at Chelsea and at Kingston, 



