208 SPRINGS, RIVERS, CANALS, LAKES, 



of iron. If the residue be of a white grey, it does not contain this 

 metal. When iron is present, Bergman directs it to be moistened, 

 and exposed to the air till it rusts ; in winch state vinegar does not 

 acton it. In order to explain the met bods of separating these dif- 

 ferent substances, we will suppose an insoluble residue to consist of 

 the five substances here mentioned ; it must first be moistened, and 

 exposed to the rays of the sun ; and when the iron is perfectly rusted, 

 the residue must be digested in distilled vinegar. Tiiis acid dissolves 

 the lime and magnesia, and by evaporation affords the calcareous 

 acetit, distinguishable from the acetit of magnesia, by its not attract, 

 ing the humidity of the air. They may consequently be separated 

 by deliquescence, or by pouring sulphuric acid into their solution. 

 The latter forms sulphat of lime, which precipitates ; but if the 

 magnesian acetit be present, the sulphat of magnesia, composed 

 of magnesia united with the sulphuric acid, will remain in solution, 

 and may be contained by a well-conducted evaporation. To as- 

 certain the quantity of magnesia and calcareous earths contained in 

 this residue, sulphat of lime is first to be precipitated : and the 

 sulphat of magnesia, formed by the sulphuric acid poured into the 

 acetous solution, must then be precipitated by carbonat of potash, 

 the quantities of these precipitates are known by weighing. When 

 the chalk and magnesia of the residue are thus separated, the iron, 

 the hlumine, and the quartz remain. The iron and the alumine are 

 dissolved by pure muriatic acid, from which the former is precipi- 

 tated from prussiat of lime, and the latter by carbonat of potash. 

 These precipitates must likewise be weighed. The matter which 

 remains after the separation of the alumine and iron is usually 

 quartzose ; its quantity may be known by weighing, and its habi- 

 tudes by fusion of the blow-pipe with carbonat of soda. Such are 

 the most accurate processes, recommended by Bergman, for ex- 

 amining the insoluble residue of waters. 



2. The alkohol used in washing the solid residue of mineral wa- 

 ters, must be evaporated to dry ness. Bergman advises treating it 

 with sulphuric acid diluted with water in the same manner as the 

 acetous solution before spoken of; but it must be observed, that 

 this process seites only to exhibit the bases of these salts. To de- 

 termine the acid, which is ordinarily united with magnesia or lime, 

 and sometimes with both, a few drops of concentrated sulphuric! 

 acid must !,e poured on, which excites an effervescence, and disen- 



