WHY SALTS ARE FOUND IN STAGNANT POOLS. 103 



ties of phosphoric acid, ammonia, and potash are taken 

 up by water from the earth. In the analysis of water 

 taken from six different springs, Graham, Miller, and 

 Hofmann found no appreciable traces of ammonia and 

 phosphoric acid. In the water of Whitley, there was, 

 in 37,000 gallons (370,000 pounds English), 1 pound of 

 potash, or 1 kilogramme in 135 cubic metres : just the 

 same in 38,000 gallons from the Critchmere spring ; in 

 32,000 gallons from Yelwool ; in 145,000 gallons from 

 Hindhead ; in 55,000 gallons from the Hasford Mill- 

 brook ; and in 17,700 gallons from the spring near Cos- 

 ford House. The water of the Brunthal spring, near 

 Munich, which is used for drinking in a large portion 

 of the city, contains no ammonia, no phosphoric acid, 

 and in 87,000 pounds, 1 pound of potash. 



From these and other analyses of spring, well, and 

 drainage water, we are not warranted in concluding 

 that potash, ammonia, and phosphoric acid are deficient 

 in the water of all springs, brooks, and rivers ; on the 

 contrary, it is quite certain that the water in many 

 marshes contains both potash and phosphoric acid in 

 notable quantities.* 



The presence of potash, phosphoric acid, iron, and 

 sulphuric acid, in the water of stagnant pools, is easily 

 explained. 



* Thus a litre (1'76 pints) of water taken from an artificial pond in the 

 Botanic Garden at Munich, left a residue of 0'425 gramme (6'5 grains), 

 which contained, in 100 parts 



Lime . 35'000 



Magnesia 



Chloride of sodium 

 Potash 

 Soda 



. 12-264 

 10-100 

 3-970 

 0-471 

 0-721 

 2-619 

 8-271 

 Silicic acid 3*240 



Incombustible constituents . . . 76-656 



Water lost . . . . . . . 23-344 



Sesquioxide of iron with alumina 

 Phosphoric acid. 

 Sulphuric acid 



100-000 



