78 



Agricultural Chemistry. 



Sea water varies in composition, dependent upon the locality 

 at which it is taken. Its composition is affected by the influx 

 of fresh water from large rivers, etc., but far out from land it 

 is very constant in composition. The average amount of total 

 solid matter is about 34,000 parts per million. Thorpe, in 1870, 

 found in the water of the Irish sea the following constituents 

 expressed in parts per million : 



Sodium chloride 26,439 



Potassium chloride 746 



Magnesium chloride 3,150 



Magnesium bromide 71 



Magnesium sulphate 2,066 



Magnesium carbonate Trace 



Magnesium nitrate 2 



Calcium sulphate 1,332 



Calcium carbonate 48 



Ammonium chloride 0-4 



Ferrous carbonate 5 



Silicic acid. . ... Trace 



In certain lakes having no connection with the ocean, the con- 

 centration of the water becomes much greater, and the total solid 

 matter may reach even seven or eight times that found in the 

 ocean. Examples of such water are found in the Dead Sea and 

 the Great Salt Lake of Utah. 



