Waters of the Dee and Don at Aberdeen. 



311 



yellow with clay, while the Don itself has more of a brown 

 colour from peat. The Don water at Aberdeen is rarely of 

 such limpid clearness as that of the Dee. 



II. — Composition of Dee Water. 

 The specimen (A) subjected to analysis by the ordinary 

 methods, was collected some miles up the river, on September 

 24th, 1850, three days after heavy rain. The river was about 

 its usual size, the rain having been preceded by a long con- 

 tinued drought. The water had a brownish tint from vege- 

 table matter, and, on close inspection, minute specks and 

 hair-like bodies could be observed floating in it. These could 

 be removed by filtration, which, however, did not sensibly 

 improve the colour. The vegetable matter was percep- 

 tible to the taste. The water contained little or no air, and 

 I have observed on several other occasions, that when the 

 water is coloured by organic matter, it is deficient in air. 

 The Dee water, in its ordinary condition is colourless, and is 

 well, often highly, aerated. The solid matter found in a 

 gallon of specimen A was constituted as follows : — 



Grains. 



Lime . 0*526 



Magnesia . . . . *. . 0*110 



Potash and soda 0-382 



Carbonic acid (in combined state) . . 0*374 



Sulphuric acid 0*275 



Chlorine 0*338 



Silica . . . . . . . 0*140 



Precipitate by ammonia from acid solution . 0*080 



Organic matter and loss .... 1*775 



4*000 



x2 



