TUNBJEtlDGE WATER. 257 
air (26), than any water hitherto knozvn. It is hard, and 
curdles with soap. 
The spring which supplies this water is situated in 
Nieder Seltzer, a village in a fine woody country, with- 
in the bishopric of Treves ; and there are few mineral 
springs which have acquired so much celebrity for me- 
dical virtues as this. The diseases, for the removal of 
which it has been successfully applied, are too numer- 
ous to be here particularized. 
To the taste it is very agreeable, and when drunk in 
moderate quantity, it exhilarates the spirits, increases 
the appetite, and produces no particular determination to 
the bowels. It is to the strong impregnation with carbo- 
nic acid, and the small proportion of soda which it 
contains, that its most important benefits are owing. 
If it be closely corked and sealed, Seltzer water 
may be kept without injury, or even alteration, for 
a very considerable time ; but, if exposed to the air, 
it soon becomes fetid. It is used as a common drink 
at table in many parts of Germany and Holland, and 
is even brought into England in stone bottles, each 
containing about three pints. A large proportion of 
Seltzer water, either genuine or artificial, is consumed 
in this country. 
8. CHALYBEATE WATERS 
292. Are such as contain a portion of iron. This is easily 
detected by the property which it has of striking a black colour 
with tincture of nutgalls. 
293. TUNBRIDGE WATER is a carbonated chaly- 
beate, the small portion of iron which, it contains being held in 
solution by carbonic acid (26). It is, hozcever, neither brisk 
nor acidulous. To the taste it is simply chalybeate; and that 
only in a slight degree. 
Its foreign contents are oxide of iron (21), a small portion of 
common salt, muriat of magnesia, and sufphat of lime (192), 
carbonic acid gas or 'fixed air (26), and other gases, but these 
only in small quantity. 
