of Mineral Waters, 229 



c Boracic acid and borax have been found in certain lakes in 

 India, and in some parts of Italy. To detect boracic acid, eva- 

 porate to one-eighth the original bulk of the water, and add car- 

 bonate of soda as long as it occasions any precipitate ; boil 

 and filter. The filtered liquor will contain borate of soda, with 

 some other salts of the same basis ; evaporate to dryness in a 

 platinum crucible, and digest the residue in three or four parts 

 of sulphuric acid, diluted with its bulk of water. If boracic 

 acid be present, it will separate in micaceous crystals. 



d Alumina has been found in a few mineral waters in the state 

 of a sulphate. It may be separated by the following process : 

 Evaporate to dryness, digest in alcohol, and re-dissolve the 

 residue in eight parts of water ; filter and add oxalic acid, 

 which throws down lime, and which being separated, leaves 

 magnesia and alumina in solution. Carbonate of ammonia 

 throws down the alumina and leaves the magnesia. 



Pure ammonia throws down both alumina and magnesia. 

 These earths may be separated by solution of potassa, which 

 dissolves the former but not the latter. 



e Manganese is sometimes found in water, but only in very 

 small proportion, so as not to amount to more than a trace. 

 Dr. Scudamore found a trace of manganese in the waters of 

 Tunbridge Wells, and it has never been discovered in larger 

 proportion. 



f It has been said that certain nitrates are occasionally present 

 in water, but such solutions can scarcely be called mineral 

 waters. If nitrate of lime be present, it will be taken up from 

 the residue of evaporation by alcohol, and may be decomposed 

 by carbonate of potassa, so as to afford carbonate of lime and 

 crystals of nitre. 



g It sometimes happens that water contains lead, which may 

 be detected by evaporation to one-eighth its bulk, adding a 

 few drops of nitric acid, and then hydriodate of potassa, which 

 gives a yellow insoluble precipitate; and hydro-sulphuret of 

 ammonia, which forms a deep brown or black cloud. These 

 precipitates may be reduced by heating them before the blow- 

 pipe upon charcoal, mixed with a little black flux. 



