CATARACTS AND INUNDATIONS, 181 



r Eptom salt, niuriat of magnesia, and carbonat of magnesia, 

 are the earthy salts which are most commonly found in waters. As 

 to the calcareous nitrat, and nitrat of magnesia, which some che- 

 mists have asserted they have met with, these salts are scarcely ever 

 found in mineral waters properly so called, though they exist in salt 



The aluminous neutral salts, and salts with base of barytes, are 

 scarcely ever dissolved in waters. Alum or acid sulphat of alu- 

 wiiue, appears to exist in some waters. 



Pure hydrogen gas lias not yet been found dissolved in mineral 

 Haters. 



Pure sulphur has not yet been found in these fluids, though it 

 csists very rarely in small quantities in the state of sulphure of soda. 

 Sulphureous waters are most commonly mineralized by sulphurated 

 iiMlroi:eij gag. 



Lastly: Among metals, iron is most commonly dissolved in water, 

 and may he found in two states; either combined with carbonic 

 acid, or with the sulphuric acid. Some chemists have supposed 

 that it was likewise dissolved in its metallic state, without an acid 

 intermedium ; but as this metal scarcely ever exists in nature with. 

 out being in the state of oxyd, combined with the carbonic or sul- 

 phuric acid, tlie opinion of these philosophers could only be main* 

 tained at the time when the carbonic acid was not yet discovered ; 

 and the solution of iron in water, without the assistance of the sul- 

 phuric acid, could not otherwise be accounted for. Bergman 

 affirms, that iron, as well as manganese, is found in certain waters, 

 combined with the muriatic acid. 



Oxyd of arsenic, and the sulphats of copper and zinc, which 

 exist iu many waters, communicate poisonous properties to them, 

 and show, when discovered by analysis, tliat the use of such waters 

 must be carefully avoided. 



Most chemists at present deny the existence of bitumen in waters: 

 in fact, the bitter taste was the cause why waters were formerly 

 supposed to contain this oily substance ; but it is now known that 

 this taste, which does not exist in bitumen, is produced by the cal- 

 careous muriat. 



There is no difficulty in conceiving how water, which percolates 

 through the interior parts of the globe, and especially through the 

 may become charged with the different substances we 

 M 3 



